Sloat Garden Guru, Simple Gardening Tips for Bay Area & San Francisco

Pest Problems

Pest eating leaves of broccoli plant

Q:	Dear Garden Guru, I recently bought some broccoli seedlings and they are growing strong! It looks like there might be some pest eating the leaves outside though. The leaves are large, but have holes and broken corners all around a handful of them. Do you know what could be causing this or if I need to spray for some pest? I never see anything on the leaves or in the garden, but I wonder what this could be. Is there some broccoli pest I need to control and if so what could I use to control it? Thank you! - Kristin in San Francisco

A:	Dear Kristin, The first suspect is cabbage looper, a very tricky caterpillar that blends in really well. They tend to lie along the midrib of the leaf during the day. Look carefully. The caterpillars can "shred" the plant leaves rather quickly. These are best controlled with Bt or Spinosad. Another likely culprit are slugs that can hide in many small, tight spaces. These can be controlled with Sluggo or Sluggo Plus which also contains Spinosad. Spinosad works on all chewing/rasping insects. All these controls are considered organic solutions.

Getting rid of garden ants

Q:	Dear Garden Guru, Hi, I have a backyard garden plot in the mission district. Before I planted, there were already two angel trumpet trees, a large morning glory plant, and some other flowering plants. I used a sheet mulching method to enrich the soil and have spinach, lettuce, broccoli, and swiss chard growing from seeds. The plants seem to be coming up just fine, but there are thousands upon thousands of ants, which swarm around the outside of the bed and on the soil and plants. I am fairly sure that they are Argentine ants, but just today, I discovered that there were some with wings and some carrying some small white things. The number of ants seems to continue increasing even though I have tried using diatomaceous earth already. I haven't seen any aphids on the leaves yet, but I am worried about this possibility when the veggies get bigger. How can I diminish this seemingly super colony of ants before they cause any damage? Thanks, - Kyla in San Francisco

A:	Dear Kyla, You certainly are gardening on a super colony. The ants with wings are preparing to swarm and create another colony. The little white things are baby ants being carried away from irrigation waters to a drier location. The Green Light Slug and Snail bait will also control ants. It does a better job than the diatomaceous earth as it is effective even if wet. It is boric acid based and works if directly eaten or adheres to the insects. If ants get it on their legs or antennae, they will clean themselves much as a cat does thus ingesting it. I suggest that you may want to also put out some Terro Ant Bait stations in the areas that have the most activity. Again, this a boric acid bait. Put the traps in locations that will not get wet.

Rose problems

Dear Garden Guru,

In my Noe Valley garden roses with 6 hrs sun are already covered with holes and brown & rust. I dormant sprayed and cont. to spray with 'rose defense' every 2 weeks on both sides of leaves. I have seen little green worms. Might Volke oil spray help? I am going to be away for a few weeks what shall I do to try and avoid any more damage?

- Heather in San Francisco

Dear Heather,

Your rose woes are part really wet weather and possibly the varieties you are growing. Some varieties are known black spot/rust machines. I would not spray with the oil spray at this time. Many of our customers have had great success with the Bayer rose and flower drench. While not considered organic, it does control all the bugs and fungus as well as feed. If you are opposed to a non organic control, I would prune back the roses that have finished flowering and remove as many of the affected leaves from top to bottom. Give them a feeding of Sul Po Mag to improve their disease resistance. Warm weather, or at least drier weather will help your bushes "turn the corner".

Safe mosquito spray recommendations

Dear Garden Guru,

Can you recommend a mosquito spray that is harmless to plants & house paint? They hang out in our potato vine at the front door.

- Caryn in Marin

Dear Caryn,

We do have two options that should work well for your situation. The first is the Bonide Mosquito Beater in a ready-to-spray bottle. It repels mosquitoes, gnats and flies in any outdoor area including patios. It is an all natural product so it's safe to use on your plants and safer for you and your family than chemical alternatives.

Here's a link to review the product online: http://www.planetnatural.com/site/mosquito-spray.html

We also carry Cedarcide YardSafe Insect repellent in a ready-to-spray bottle. It also repels mosquitoes and other flying insect and is 100% organic. It can be used on vegetables and any other plants you might have, plus it can be used indoors if necessary.

You can see more info here: http://www.planetnatural.com/site/cedar-repellent.html

With both of these products I can not guarantee what they will do to house paint. Your best bet with any product you purchase to battle the mosquitoes is to test it on a small section of painted area to see what effect it has. They are both natural oils so I don't believe they will cause damage, but oils can potentially make some paints run, so please do be careful and do a test.

Also, the websites that I've linked you to do sell these two products, but I would alert you to the fact that their shipping charges are rather high, so your best bet would be to simply visit any of our Sloat stores to get the best value. Plus our team members can continue this discussion with you in person if you like. If there is a particular Sloat store that you like to shop at, just let me know and I'll be sure that they have these choices in stock for you so that you do not waste a trip.

Pill bugs and earwigs in the garden

Dear Garden Guru,

We live in a high humidity coastal climate and have a large population of earwigs and pill bugs. We are highly against using insecticide due to harming of good insects. Are earwigs and pill bugs harmful to plants and vegetables?

- David in Pacifica

Dear David,

Pillbugs, and especially earwigs can be harmful to plants. Earwigs are notorious flower petal eaters. They can quickly destroy Dahlias, daisies, and other prized flowers. They feed on tender seedlings and new transplants. Pillbugs, in small numbers are not as harmful. They feed mostly on garden detritus. In larger numbers, they will aggressively eat seedlings just as they emerge from the soil. Sunflowers, beans, and peas are most susceptible. There is a safe, organic control for these bugs, Sluggo Plus. This product contains iron phosphate, a naturally occurring mineral, and spinosad a bacteria/actinomycete The bait has to be ingested therefore, it does affect predatory beneficial insects. The iron phosphate kills slugs and snails and the spinosad works on ants, earwigs, pillbugs.

Safe, organic ways to get rid of caterpillars

Q:	Dear Garden Guru, I have a dwarf lemon tree on my deck and it seems to be infested with inchworms, small green inch worms. What is a safe, organic, non-toxic way to get rid of these. Are there any predators like praying mantis etc? Thanks for your help. - David in San Francisco

A:	Dear David, The easiest and safest way to rid yourself of the caterpillars is to spray your citrus with Bonide Caterpillar Killer, also known as B.T. Bacillus thunbergiensis is a naturally occurring bacterium that when ingested by caterpillars, causes them to stop feeding and subsequently perish. It is safe for wildlife, kids and pets. There is not a commercially available predator to control inchworms handily. Praying mantids would consume a few but they do not hatch until about May.

Getting rid of baby tears

Q:	Dear Garden Guru, Help! That beautiful little patch of Baby Tears in my shady flowerbed has turned into a massive tidal wave of green, engulfing its less aggressive neighbors. What is the best way to keep it under control? - Sue in Dublin

A:	Dear Sue, Baby Tears grows best with ample water/moisture and regular exposure to fertilizers. To culturally slow down the beast, avoid feeding it and reduce the watering if the companion plants will accept this. You may have to physically remove it by scraping it off, including some of the underlying soil it has rooted into. Do not apply mulch around the baby tears as it will find this looser material easier to root into. Once you have it as far back from companion plants as you want, you can periodically spray encroaching growth with Burn Out, a vinegar based weed killer that will kill back only the foliage sprayed.

Removing liverwort permanently

Dear Garden Guru,

Every year there is more liver wort in shady areas of my 1/2 sunny garden in Noe Valley. I have just scraped a lot of it off with a trowel. I plan to amend & plant some cool vegetables there. What can I do to remove it permanently?

- Heather in San Francisco

Dear Heather,

Liverwort loves moisture, loves nutrient rich soil. Amending your soil with a compost should help as the top of the soil where the liverwort lives will tend to dry out faster. Avoid using liquid fertilizers in areas where liverwort thrives. You are better off, mixing in a dry fertilizer into the soil or using a preplant fertilizer such as Sure Start and incorporating a slow release such as Osmocote at the same time. Liverwort can be killed by spraying it with vinegar. Household vinegar is a 5% concentration that will work on rootless liverwort (it is not strong enough for other weeds). We also have a vinegar based herbicide called Burn Out that has a higher 6.25% concentration. As for permanent eradication, the more you are able to scrape away and dispose of BEFORE it flowers (those odd umbrella-shaped structures), the less spores you will have to hatch at later dates.

Where did our "friend" Oxalis come from?

Q:	Dear Garden Guru, I see your very first question for Feb is about our dear friend, Oxalis. Maybe you can help with mine on the same subject: Is the yellow oxalis that is covering our hills (see Bernal Heights et al) and sprouting in our gardens now a non-native variety? Is it in fact from South Africa as local legend has it? And what exactly is its genus/species? I've researched (and argued about) this issue with many but cannot find a definitive answer. Thanks for any help! - Ed in San Francisco

A:	Dear Ed, This pretty little non native is now considered an invasive weed threat. It is indeed from South Africa and is known as Oxalis pes-caprae (Synonym O. cenua). It does not spread by seed but asexually by lateral roots and many small bulblets that are formed along it's tap root under the soil. At least there is no evidence that it sets seed. It spread first to the Mediterranean in the 19th century and then to the Americas. It was mentioned in Bailey's Horticultural Manual in the 1930's after it was probably collected for use as an ornamental. There is no mention of it being in California prior to 1925. It was first noticed (or rather recorded) to be prominent in southern California orchards and vegetable fields in 1951. How did it spread? Bulblet contaminated soil on shoes, tractors, tires, tools, or innocently planted by people who dug it up to plant in their yards. It could have been spread by imported bareroot trees. In any case, it certainly has taken "root" along our coast.

Getting rid of gnats

Dear Garden Guru,

What is the best way to get rid of gnats? I have tried the vinegar trick, the water trick, the potato trick and none seems to work. I even tried a few different sprays. Please help.

- Kelvin in San Francisco

Dear Kelvin,

You don't say what type of gnats are bothering you. I will assume you are referring to gnats in your potted plants. The best way to get rid of them is to apply beneficial nematodes to your containers (Fungus Gnat Destroyers). The nematodes will feed on the hatched maggots and pupae in the soil thus breaking the cycle. You can attach yellow sticky traps (Gnat Stix) to trap the adults at the same time. The gnats are attracted to soils rich in organic matter (peat moss, manure, compost) and kept too wet.

Ants in potted plants

Dear Garden Guru,

I have teeny tiny ants, millions of them, in the soil under some of my potted plants. How do I get rid of them? They are climbing up into the pots and that can't be a good thing for my flowers. Thanks.

- Elizabeth in San Rafael

Dear Elizabeth,

You can get rid of your ants with the Green Light Slug and Snail (it also is effective on ants, sow bugs, and earwigs). Sprinkle some under the pots as well as the soil in the pots. This is an organic remedy based on boric acid.

Keeping a fat happy raccoon out of the garden

Q:	Dear Garden Guru, What are your suggestions for keeping a fat happy raccoon out of the garden -- my garden is small and totally fenced, but that is not a deterrent. - Sheila in San Francisco

A:	Dear Sheila, If this critter is a regular visitor, it is possible that he/she lives on the property. Look about for openings under stairs, access under the house or into the garage. Make sure all these openings are screened. Do not leave garbage cans and pet food outside. Harvest ripe fruit from trees. If it is a lawn area or bed that is being dug up, use one of the granular repellents such as Critter Ridder or Repels All in the areas being disturbed. If there is standing water such as a birdbath that can be used for drinking or "hand washing", empty it.

Getting oxalis out of the garden

Q:	Dear Garden Guru, I have very abundant oxalis in my garden beds. We just moved to this flat, our neighbors have just been spraying weed killer every now and again to keep it at bay. They haven't planted the beds and stopped the weed killer when we told them we wanted to plant the beds. I want to plant vegetables and flowers including, bulbs, sweet peas along the fence and abutilon, clematis etc. Any thoughts? I have two sections of about 15 by 5 ft beds. - Nalani in San Francisco

A:	Dear Nalani, You should attempt to dig as much of the Oxalis out as possible. Mature plants have many small bulblets at the base. Sifting the soil after you have dug what you can will help capture any loose bulblets. Cover your beds with the lasagna method of mulching. First wet newspaper, then cardboard, then compost or forest mulch, then more newspaper, planting mix, cardboard, then compost. You can plant directly into your lasagna layers. Any Oxalis trying to resprout will be depressed by the mulch layers.

Stop cats from using my vegetable garden as a litter box

Dear Garden Guru,

How can I discourage neighborhood cats from using my vegetable garden as a litter box? How can I keep them out?

- Emily in San Francisco

Dear Emily,

Sloat carries a couple products that can help you. The first is Critter Ridder. It is a granulated, pepper based repellant that is safe too use around your vegetables. You can directly sprinkle the product around your garden. The second is Liquid Fence Dog and Cat repellent. It has a much stronger smell and is designed to be sprayed around the perimeter of the yard or garden boundary. Once dry, you will not notice the smell.

Another trick that can be used is to sprinkle orange peels where the cats are going. They dislike the smell of orange oil. It is possible that the product Orange Guard will work as well but it's not listed on the label for this purpose.

How to keep the neighbor's cats away

Q:	Dear Garden Guru, Recently a neighbor's cat has taken to coming into our garden and defecating in various areas - digging up the dirt in potted freesia bulbs that had finished blooming and digging up the baby tears ground cover. The garden was a sanctuary but is now becoming one big sandbox for this cat and it's pretty disgusting to have to pick up after it. It's not only smelly but unsanitary as well. Is there any way to keep the cat away? Please help. - Mary in San Francisco

A:	Dear Mary, The Bonide Dog and Cat repellent can be sprayed along the perimeters of the garden as well as in the areas that are being disturbed. Cats also dislike citrus oil. Orange peels that have been chopped fine in a food processor can be sprinkled in pots. Bamboo skewers, cut into 3"-4" lengths, and spaced 3" apart can be in inserted in pots and planting areas also to prevent digging.

Fighting bermuda grass

Q:	Dear Garden Guru, How do I kill bermuda grass - without using pestisides. Desperately seeking organic solution. - Victoria in San Francisco

A:	Dear Victoria, Fighting Bermuda grass is a struggle, whether by organic means or no. There is a spray we carry called Bonide Lightning Fast. It is basically a strong soap solution. This will burn out top growth very quickly, especially on really hot days. 10% to 20% solutions of Vinegar will also work. If the patch is small, consider boiling water which will kill the roots too. The problem with Bermuda is the stolon root system which readily breaks. One little root piece left and it regrows. The small seeds it forms are another issue. After you have burned back the top, rent a sod cutter. Set the sod cutter on the lowest setting to strip as much of the stolon mass away as possible. This is the expensive part of the venture as the removal of dirt and debris can be costly. After removal, utilize the lasagna method of mulching the area: first cardboard/newspaper, mulch, more newspaper/cardboard, and lastly, more mulch. Please know that you probably will not have found all the stolons and they will happily invade the new space. Hand pull these new patches as they arrive. Do not let seed heads form! Persistence will pay off as long as you realize that you will never completely get rid of it. Cohabitation is a more likely result.

Dog pee is killing plants

Q:	Dear Garden Guru, Help! My garden is dying! My container plants, lavender, succulents and potato vine are all dying rather quickly. (Only my coleus are surviving) I have tried plant food, different watering techniques, sluggo and more but it just look dead. I live in the Mission, get areas of good sun and put plants in their proper "climate". We do have three dogs in the building that use the yard as their bathroom though--much to my chagrin. Can pet pee and poop toxify the environment? Any help is appreciated. - Uda in San Francisco

A:	Dear Uda, I am afraid that dog pee and to a lesser degree, excrement can harm plants. This is especially true in warmer or hot weather. Dog pee contains strong ureic acids that will quickly burn foliage or roots if not washed away quickly. Male dogs have a tendency to aim at containers and hit all the corners. Plants that have been marked are more subject to burn in that the other dogs will pee over the first dog to mask the scent so the plant receives a double or even triple dose. You may want to use a repellent such as Repel, Shotgun or Bonide Dog and Cat to keep the dogs away from your plants.

Insect bites after working in the garden

Q:	Dear Garden Guru, I am getting a lot of bites from invisible insects when I work in my garden. I suspect mites. Is there any way to get rid of them (an organic solution preferred if possible)? Thanks. - Jon in Mill Valley

A:	Dear Jon, I suspect your invisible biters may be juvenile mites known as chiggers. If you have tall weeds or grass keep them cut down. Blackberry thickets and creek sides are also well known harbors for chiggers. The juvenile mites hatch and mature beneath the soil level so applying beneficial nematodes may help eradicate them. Other hard to see bugs are small midges that bite very much like mosquitoes. Apply mosquito dunks to ponds and water features such as fountains and bird baths. Use an insect repellent on your garden clothing that contains .5% Permethrin. Yes, this is a synthetic chemical that acts like pyrethrum but it is certainly safer for you than DEET and you are spraying your clothing, not the environment.

Gnat troubles on indoor plants

Q:	Dear Garden Guru, I have been getting gnats in many inside plants. I had them this winter and I changed soil and cleaned plants time and again and thought I finally was Ok, but they keep returning. I have had indoor plants for 40 yrs and never a problem till this winter. Please help me thanks. - Joan in San Rafael

A:	Dear Joan, The soil or fungus gnats become a problem when the soil is kept too moist and not allowed to dry out much between waterings. The larvae of the gnats feed on the small fungi that are decomposing the organic portion of the potting soil, primarily peat moss and mushroom compost. Too many larvae in a pot and they can begin to feed on the plant roots as well. To control them, keep your plants on the dry side. You have already gone through the changing of the soil. Sloat carries beneficial nematodes (aptly named fungus gnat destroyers) that can be applied to the problematic containers. The nematodes eat the larvae thus breaking the cycle. Small yellow sticky traps called Gnat Stix can be attached to the rims of the pots to catch the annoying adults.

What is eating my container plants?

Q:	Dear Garden Guru, Dear Garden Guru, something is eating our very lovely bay laurel container plant - only the new growth leaves at the top. Same goes for the spearmint nearby. Do you know what this is and is there anything to do? - RR in San Francisco

A:	Dear RR, Chewing insects are not known for bothering Bay Laurel. I suspect it is probably snails and slugs bothering both the aromatic herbs. You can apply Sluggo or Sluggo Plus (this one includes Spinosad that gets chewing insects, just in case) to the containers. The baits are non toxic to pets, birds, amphibians, etc. I would check the laurel for small baby snails hiding under the leaves or at the base of the mint. Thanks for choosing to garden with us.

Dealing with leaf miners in chard

Q:	Dear Garden Guru, I just noticed that I was getting weird coloring on some of my swiss chard and spinach leaves. It looks like something is burrowing in the leaves. I did a little research and narrowed it down to leafminers. What can I do to get rid of these pests? - Maria in San Francisco

A:	Dear Maria, Those are indeed leaf miners. The adults are small black flies that emerge from small brown pupae in either your soil or the neighbors. They are active from April to September. The adult flies lay white eggs on the undersides of chard, spinach, and beet leaves. The young burrow between the leaf surfaces, and once there, are impervious to sprays. The goal is to keep them from maturing. Check leaves often for signs of eggs and destroy them. Remove portions of leaves that are infected by leaf miner and dispose of them (don't compost them). You can protect plants from the flies by covering them with floating row covers (We sell Harvest Guard). You can also spray your plants once a week with the organic Spinosad. It works by killing new egg hatches.

Getting rid of wild flies

Q:	Dear Garden Guru, Last year I noticed tiny white flies in my garden. They cling to the underside of leaves and become active when I water plants or walk thru the garden. I thought that they would die off during winter rains. Unfortunately, they are still there and are spreading throughout the garden. How do I get rid of these tiny pests? - Tyler in Mill Valley

A:	Dear Tyler, Whiteflies are hard to get rid of. You may have to do battle on multiple fronts. Whiteflies are attracted to specific plants; Lantana, Hibiscus, Verbena, Tomatoes, Petunias, etc. If you have a severe infestation on a particular plant, you might consider removing it. The larvae are found on the undersides of leaves. To be effective, the undersides of the leaves must be sprayed. Bonide All Seasons Oil or Spinosad will be the most effective. Ladybugs and their young will eat whitefly eggs and larvae. As a last resort, the Bayer All In One or Tree and Shrub Formula are effective systemic insecticides. You can not use these chemicals on food plants. I would ask your neighbors if they also have a whitefly problem. If they do, you should all work together to ensure successful eradication.

Fungus gnats on my ficus

Q:	Dear Garden Guru, I have some little black flies in my apartment and today noticed there were more of them gathering around my ficus plant...the soil in the pot. Without using chemicals, can you tell me how to rid my home of this pestilence! Thanks. - Nina in San Francisco

A:	Dear Nina, Those little buzzing pests are fungus gnats. They become a problem when houseplants (or greenhouse plants) are over-watered or when the soil stays constantly moist. Overly moist soil is more relevant to the gnats indoors because the temperatures stay warm. The adult gnats lay eggs in the soil. The larvae hatch and begin to feed on the decaying organic matter of the soil (and can sometimes harm roots if their numbers are great). They pupate and then emerge as the annoying gnats to start the cycle again. The cycle can be broken if the soil is kept drier, allowing more time between watering. Repotting a plant into fresh soil will also help. There is also a product called Gnat Exterminator. They are beneficial nematodes (microscopic soil dwelling "worms") that prey on the gnat larvae. They are applied as a spray to the infected foliage. Sloat also carries a miniature sticky trap, called Gnat Sticks that can be placed in the pot to trap the adult gnats.

Get the varmints out of my yard

Q:	Dear Garden Guru, How do I get the skunks, feral cats and etc. out of my yard? No matter how I fill the big holes under my fence, they dig new ones and come in. The cats also use my yard as a litter box. - Eunice in San Francisco

A:	Dear Eunice, Sloat will be carrying a new product called Shotgun Repel All later this spring. It is designed to deter those harder to be rid of animals such as skunks and raccoons. In the past we recommended Critter Ridder for the skunks but heard that the product did not help. What did work for skunks was attaching rags soaked in ammonia at their entry points to the yard. It is also important to find any uncovered holes or crawl spaces that go under the house or under stairs. As far as the cats go, the Bonide Dog and Cat repellent has been effective. Cats also dislike orange oil. Some people save their orange peels, shred them very small and apply to the areas where the cats are defecating.

The science behind companion planting

Q:	Dear Garden Guru, I just read your blog from 2008 on companion planting which I found very interesting! It explained why I have so little problems with pests in my combined vegetable/flower and herb garden. How close do these companion plants need to be to each other? I assume the ones which add nutrients to the soil need to be quite close, but what about those that attract beneficials/repel pests? Can they be nearby or in separate raised beds? Within what distance? Thank you very much. This is a wonderful web site. - Susan in American Canyon

A:	Dear Susan, Companion plants that repel pests/attract beneficials work the best planted close to the target plants. This can be anywhere from 1' to 6' away. To provide haven for beneficials, their preferred plants can be planted in another bed or at the perimeter of the garden like hedgerows. Keeping beneficials close by is often sufficient. Plants, when attacked by pests, exude chemicals/hormones that actually attract nearby beneficial insects. Here is a link to our blog post about companion planting: http://sloatgardens.blogspot.com/2008/05/companion-planting.html

Get these skunks out of my yard!!

Q:	Dear Garden Guru, Hello! My problem is so many rowdy/noisy and yes, smelly Skunks in my yard. How I can I send them elsewhere without the use of poisons? I refuse to use anything that will kill them or make them violently ill! Just want them out of our yard.They're so noisy they keep me up at night. :-( HELP! I've heard of electronic repellers...do they work? Thanks for your speedy reply! - K.G. in San Francisco

A:	Dear K.G., Since you seem to have a family of skunks regularly visiting the yard at night, I'd almost assume that they live under your house. The first thing I would do is check for openings and check that all crawl ways to gain access under the house are covered. Skunks can readily find that warm spot where there is a gas pilot light. Are your garbage cans secured? Are they digging or eating unpicked fruit? We carry a product called Critter Ridder that can be applied as a granule or spray. It can be applied to the periphery of your yard and where they are creating a nuisance. Applications will be best in those areas where the animals can walk in to gain access. They are not habitual climbers of fences or trees.

Dreading Aphids

Q:	Dear Garden Guru, I have aphids on my anenomes and have treated them with insecticide soap a number of times such that the aphids seem to be gone, but then they come back within a couple of days. I have also tried dousing them with water, but to no avail. Besides controlling them on the plants outside, I would like to bring some cut flowers inside but am afraid of spreading aphids to houseplants. - Susan in Mill Valley

A:	Dear Susan, I am sorry to hear that you are being plagued. Rather than the insecticidal soap, you may want to consider trying Rose Defense. We have been very satisfied with the results of this product for years. Beneficial ladybugs are also back in the stores. It may be to your advantage to release a box so that they can hunt down the hidden aphids in your garden that are unseen. As far as cutting flowers to bring inside, a thorough washing with the hose should do the trick. I have a feeling the aphids are hiding under the foliage or on unopened buds. Be sure to spray under the leaves as well.

Peach borer pest

Q:	Dear Garden Guru, I just noticed that my Donut Peach tree has some clear colored, sticky (sap type) substance on the branches ... what is this and how do I get rid of it safely? - Kathy in Orinda

A:	Dear Kathy, If the sap you see is on the trunk and lower branches of the tree, I suspect that you may have Peach borer damage. The peach borer looks like a metallic blue wasp and lays its eggs in the bark. The larvae burrow in causing sap (and you may see frass- a sawdust like substance) to leak from the holes. You can kill the larvae by inserting a thin wire or unbent paperclip into the holes. You may also want to spray the bark of the tree with Bonide Borer Miner Killer (available at any of our stores). If holes are not in evidence, the tree may be showing signs of gummosis disease. This occurs when the tree has received too much water or has poor drainage. This can also occur due to winter cold damage of new growth triggered by a late summer pruning. Make sure that you feed the tree this spring and again in mid summer to promote vigor. The Miracle Gro Fruit Tree and Citrus spikes are easy to use…or use EB Stone All Purpose Food around the drip line. Be sure to water after feeding. Do not mulch your tree so the soil holds too much water.

Keeping plants healthy with beneficial insects

Q:	Dear Garden Guru, I have a fairly shady back yard in the North Beach part of SF. I have put in Heuchera a couple of times. They seem to last/be healthy a year or so and then die. When I go to check the dead looking plant, it comes up in my hand without apparently any roots left. Is something eating the roots? Or possibly rotting them? The plants can look healthy and the next time I go down (a week or so) the leaves have all drooped and it is starting to dry out. Thank you. - Phyllis in San Francisco

A:	Dear Phyllis, Other than gophers, (you would see the evidence of mounds of earth) roots can be attacked by weevil larvae and cutworms. They are especially prevalent in shaded areas. Other plants that usually fall victim are Azaleas, Impatiens, Primrose, and Iberis. The best plan of action would be to apply beneficial nematodes to the soil. The microscopic nematodes search out, attack, and subsequently vanquish soil borne grubs and larvae. If the roots were rotting, other plants in the area would likely show symptoms of stress as well. These are available via mail order through any of our stores.

Eek, a snake! How do keep them out of my yard?

Q:	Dear Garden Guru, I live on the west slope of Twin Peaks, adjacent to many open spaces. I am morbidly afraid of snakes and I have seen several in the area and one in my yard. I am landscaping the backyard and need to know the best way to keep snakes out of my yard. Thank you - Susan in San Francisco

A:	Dear Susan, I cannot help you with your phobia of snakes, but be assured, the snakes that you have seen are probably not poisonous. I suspect that you have seen garter snakes (black w/ yellow stripes or orangey green) and bull or gopher snakes (ochre yellow and brown to 6' long). While there may be an occasional Pacific rattlesnake, they tend to live in Manzanita/oak chaparral by creeks. Gopher and bull snakes hunt frogs, lizards, rats, mice and birds. To keep them from intruding, I would not have a backyard pond or plant material that uses a lot of water. Any area that is irrigated more than 3 times a week will entice little frogs and salamanders. Bird feeders may invite little field mice. Overgrown shrubberies and ivy will be appealing to rats. You may want to consider putting out some of the new safe rodent baits (they only target rodents, not cats, dogs, birds, etc) to reduce your chances of having rats and mice about. There is also a snake repellant called, fittingly, Snake Away. Sloat does not carry it but it is available online. It is basically napthalate (the main ingredient in moth balls). You may want to consider sprinkling moth crystals or some such along your more "wild" borders.

Cymbidiums

Dear Garden Guru,

I just obtained a tall and heavily flowering Cymbidium orchid and would like to stabilize it by transplanting to a deeper and wider pot. Is this advisable, and what sort of growing medium is best?

- Tom in San Francisco

Dear Tom,

Yes, those Cymbidiums certainly can be tippy. I would advise you NOT to transplant your orchid until after it finishes blooming in the spring. Wider is much better than deeper, as a deeper pot will hold too much moisture and could possibly rot your plant. For planting, you could use our fine orchid bark OR the orchid planting mix. The orchid planting mix is of course heavier and would act as a better ballast for a tall Cymbidium. We do have an orchid seminar coming up on the evening of February 6th at 5:30. It will be held at our store on Sloat Blvd. Glenn Smith, who will be giving the talk, is a wealth of knowledge on orchid repotting.

Rhododendron

Dear Garden Guru,

I have several rhododendrons in my backyard, and all are thriving except for one. All of the plants were planted about 4 years ago, and have done well. This one rhodendron, however, started to droop over the past month. It now has the buds growing on most of the stems, but all of the leaves are brown or yellow and are drooping. Is the plant dead? Or is there a chance it will come back in the spring? What is wrong with it?

- Cheryl in Corte Madera

Dear Cheryl,

The symptoms you describe on your Rhododendron can be caused by a few things. Drooping leaves are an indication of root rot or crown rot. If the plant is buried too deeply or stays water saturated too long, the leaves will droop. If the temperatures drop below 35 and the soil is not wet enough, the leaves can turn brown and droop due to desiccation from cold. Some varieties of Rhododendron are more affected by cold than others. Sometimes gophers can be a problem. There is also a chance that Sudden Oak Death spores have infected the plant. I am concerned about the fact that the leaves are brown and yellow. Were they this color before the leaves began to droop? I would suggest that you aerate the soil around this plant to improve drainage and water penetration. If the soil is dryish, even after the rain, I would water. DO NOT feed the plant as this will often exacerbate a problem in an already stressed plant. You may want to dig up the plant and replant it again in a higher position. This will also give you the opportunity to examine the roots. If they are blackened, you have root rot and the plant will unlikely survive. If the plant has been cold damaged, it will rebound again in the spring. Hope this helps.

Caterpillars/slugs/snails

Q:	Dear Garden Guru, I have a new meyer lemon brought home in the past year. The leaves have recovered from initial yellowing, but are now being chewed on by something. I haven't seen the culprits, but a couple of leaves have been chewed almost in half. What would be a good approach for thwarting the unidentified culprits? (This is in the Excelsior area of San Francisco) - Laura in San Francisco

A:	Dear Karen, The main culprits are usually either caterpillars or slugs and snails (and sometimes earwigs). With slugs or snails you will generally see holes forming in the middle of the leaves. Plus there is usually a slimy trail left behind on the leaves too. All of our Sloat locations carry slug and snail controls that would help if this is the case. Caterpillars will eat the leaves from the outside in. The outer edges of the leaves look like they have bite marks on them. They can certainly eat a fair amount of leaves on a citrus tree. If this is what is happening, there is really only one active ingredient that works against caterpillars, called Bacillus thuringiensis (Bt). You can also find this at any of our stores, made by Safer Brand. Earwigs can do damage similar to that of caterpillars, but caterpillars are the more frequent attacker. If you find that the caterpillar killer is not solving your problem, then our Greenlight Slug and Snail bait also works on earwigs and could potentially handle multiple problems for you at the same time. Additionally, spying on your tree late at night with a flashlight might help you discover what it is that is feeding of your plant. I hope this helps. As always feel free to visit any of our garden centers for more expert advice.

Mealy Bugs

Q:	Dear Garden Guru, I seem to have a mealy bug situation primarily in my succulents. I have used a fungal oil, but they seem to come back. Now what!! - Claudia in San Rafael

A:	Dear Claudia, It is common for succulents to get mealy bugs so you are not alone. The fungal oil did not work because mealy bugs are not affected by fungus treatments. The best way to eradicate these insects is to swab them first with rubbing alcohol which melts away the white waxy coat they wear. Follow up by spraying Bonide All Seasons Oil or Bonide Eight All Insect spray. Make sure that you have watered them in advance of any treatment.

Tomato issues

Q:	Dear Garden Guru, My tomato plants (2) were growing like mad and had many blooms. I was out of town overnight and when I returned the stems were starting to look slimy, then they quickly died, turning black. Can you tell me why? - Dolores in Pacifica

A:	Dear Dolores, I am sorry to hear about your tomatoes. Crop failure always hurts when it hits established presumably healthy, vigorous plants. I think that you were struck by either Late Blight of Tomato or Bacterial Blight. The sliminess suggests a Bacteria and this is a disease that can ravage a plant very rapidly. The spores are airborne or carried in the stomachs of beetles such as the Diabroitica or Cucumber Beetle (the green "ladybugs"). The disease is likely to occur if we have warm or hot days and mild nights suddenly interrupted by much cooler, damp weather. Overhead watering will also stimulate an outbreak. I hope that you have removed the plants so that spores will not over winter in that spot. It is advisable to change the location of your tomatoes next year. To control the disease and reduce its spread, EB Stone Copper spray is recommended. I hope this helps. Please feel free to visit any of our store locations to get more specific instructions on how to use the Copper Spray, or just get more instructions for this year.