Ask the Garden Guru

Frost damage in lime tree

Dear Garden Guru,

I have a 5 year old lime tree that has been frost damaged. Is there anything I can do to save the tree?

Pete in Novato

Hi Pete,

Of the citrus, limes are the least tolerant of cold weather. They are notorious for defoliating. After our cold snap, I imagine that your tree looks forlorn but do not lose hope for its recovery. You will not know the extent of cold damage until March. It may be that some of the branch tips and twigs have been killed but the rest of the tree should still be quite alive. If you scrape off the bark and see green beneath, it is alive. Wait to prune or feed until late March. New leaves should resprout in April. If the tree is in a container or planted where it will not receive rain, water periodically through the winter to keep the soil from completely drying out. If there is a chance we will have another freeze, cover the tree with burlap, a sheet or frost blanket to prevent further injury.

Will birch trees grow in the Sunset?

Dear Garden Guru,

We are redoing our front garden and need to remove our lawn and all of the bushes. We live in the sunset and want to know if birch trees would do well in that area or if you have any other recommendation for trees, plants or flowers that do well in a neighborhood in the Sunset off of Sloat Blvd. Thanks!

Michelle in San Francisco

Hi Michelle,

Birch trees may have a difficult time with the winds and salt air that you have there. If you like the habit of birch, Melaleuca quinquenervia (Cajeput) will give you a similar look. Other trees to consider are Arbutus Marina, Eucalyptus ficifolia and Schinus molle.

There are a number of plants and shrubs that will do well in your location, I suggest either contacting our design department at 415-388-3754 or visiting the store by the zoo and having one of our associates show you around.

Caring for fruit trees

Dear Garden Guru,

We have a mature apple tree and a peach and plum tree that are about 2-3 years old. Last year all the trees got diseased. The apple with powdery mildew and the peach and plum with peach tree curl. What can we spray the trees with to protect them and how much should we prune ? Also when should we be spraying them? The trees are mostly bare right now. Thanks.

Mala in San Francisco

Hi Mala,

Fruit trees are normally sprayed 3-4 times from late fall through early spring. The first spray is when the leaves have dropped, second in December/January, third NOW in early February and then again at bud swell. Use a copper spray such as EB Stone Copper Fungicide or Lily Kop-r-Spray. This will control peach leaf curl, shot hole fungus and powdery mildew. Your plum tree probably had leaf curl due to an aphid infestation. The small, black aphids attack newly emerging foliage and wrap the leaves and cause the leaves to wrap around them thus protecting them from sprays. The plum should be sprayed after flowering with Greenlight Rose Defense or Neem Oil which works to deter aphids in the first place. When pruning, remove branches that grow towards the center of the tree, crossing, or branches that are too close together. The aim is to open the middle of the tree to light and improve air circulation. Plums require heavy pruning as they produce a volume of shoots and sprouts each year. Cut out vertical growing shoots and cut others by 1/2. Peaches fruit on new one year wood so require heavier pruning. Remove 2/3 of the previous years growth by a combination of removing 1-2 of every 3 branches and heading back the rest. It is difficult to adequately explain pruning through writing. We do have some Pruning seminars scheduled this month. You can find them on our website, www.sloatgardens.com.

Fruit Tree Pruning – Feb. 27 at San Rafael Sat. 10:00 am, Feb. 28 Mill Valley Miller Ave Sun 10:00 am
Pruning 101– Feb 17 at Sloat Blvd. Wed 5:30 pm and Feb 21 at Pierce St. Sun. 10:00 am.

Planting and care of fruit trees

Dear Garden Guru,

We purchased a home within the last year and we would like to plant fruit trees. We have a fairly large backyard with sun for about 3/4's of the day and a medium sized front yard with full sun. My biggest question is that we get lots of wind late spring through early summer. Where is the best placement for the fruit trees and how can we best protect the blooms from the high winds? Thanks so much.

Michelle in San Rafael

Hi Michelle,

Fruit trees do best with full sun. It sounds like your yards have optimum light. As for the wind, they are not as detrimental to the blossoms as you may think. Pollen at least is blown from one flower to another if not many bees are out working. Rain during flowering is far worse as the bees do not come out and the flower is pelted to the ground. You will want to stake the trees when you plant them. Orient the stakes in the direction of the prevailing winds. Position the tree so that the bud graft (the crook at the bottom) is positioned away from afternoon sun. The worst wind can do is dry out the foliage. A water stressed tree is more likely to shed young fruit so water new fruit trees deeply at least twice a month during windy times.

Apple tree recommendation for Potrero Hill

Dear Garden Guru,

I would like to plant an apple tree in my sunny back yard on the north face of Potrero Hill. My friend in Seattle particularly likes Elstar and Honecrisp both grafted on a single rootstock. I would like a tree no more than ten feet tall and apples that will pollinate one another. what rootstock do you recommend and do you have a recommendation regarding these or comparable apples varieties for Potrero Hill? thank you very kindly for your answer.

Sharon in San Francisco

Hi Sharon,

The varieties Honecrisp and Elstar are not suited for our climate. The apple varieties that do best in San Francisco are Fuji and Yellow Delicious if you want something that is considered self fertile. Gala does well here but needs a pollinator. Of course, when 2 trees are planted, the pollination rate is that much better. We have Fuji on a UD (ultra dwarf) rootstock. The resultant tree will get no higher than 6″. We also have semi dwarf but these will get 12′ to 15′ tall unless pruned back. Because space is a premium, we also carry espaliered apple trees with 6 varieties (3 tiers, 1 variety per left or right arm): Fuji, Gala, Jonathon, Red Macintosh, Braeburn, and Gravenstein.

Hundreds of slugs on my lemon tree. help!

Dear Garden Guru,

We are overrun with snails. Our beloved Meyer lemon tree is INFESTED with about 200 snails. They're everywhere and they are quickly devouring the tree. We have a dog and a small child who spend a lot of time in the backyard, so snail bait is not an option. Any suggestions? We've tried the beer in the pie dish route, and that didn't work. I would hate to cut away all the affected branches, as there basically wouldn't be any tree left. We don't want to use poison, as we would like to use the lemons. Many thanks.

Amy in

Hi Amy,

There is a safe, non toxic bait available for snails! It is called Sluggo and has been listed by OMRI (Organic Materials Review Institute). It is composed of iron phosphate that occurs naturally in the soil. This compound is highly attractive to slugs and snails. They ingest the pellets and this causes them to stop feeding on your plants (or anything else). They become less mobile and crawl away to die. Dead snails are not toxic to birds or other wildlife. Uneaten pellets decompose and go back into the soil. The bait is not toxic to pets, children or other wildlife. The iron phosphate will not make your lemons toxic, they will more likely feed your tree.

New leaves curling prematurely on fruit tree

Dear Garden Guru,

Hi, I have a nectarine/peach tree in my backyard, and the new young leaves are prematurely curling and have "blister like" formations on the leaves. I also notice a trail of ants going up and down the trunk of the tree. Is this a fungus? Bug? or something else that is causing this? Please let me know what I can do to combat this.

Chris in San Francisco

Hi Chris,

You have a fungus known as peach leaf curl. It also affects nectarines. You can spray your tree now with EB Stone Copper spray (a concentrate) or the Bonide Copper Spray (Ready to use). The important ingredient is copper sulphate. This will arrest the spread but affected leaves will still fall prematurely. The best way to prevent it,is to start a spray program in the fall when the leaves fall. Spray again in December and again when buds swell in the spring. If your neighbors have peaches or nectarines, maybe you all can spray at once. The spores can be carried with the wind down the street and over the fence. As for the ants, I suspect they are farming insects, either scale (seen as dark, hard lumps on smaller twigs) or aphids (probably green curled up inside leaves). These insects can be killed by spraying with Bonide All Seasons Oil. The convenience to you is that the copper spray and the oil spray can be mixed and sprayed at the same time. Do not spray when temperatures will exceed 75 degrees. You can also deter the ants by applying a sticky barrier at the base of the tree such as Tanglefoot. Apply a 4″-5″ high band around the trunk to literally stop them in their tracks.

Keeping critters away from an apple tree

Dear Garden Guru,

I have a beautiful Fuji apple tree in my backyard, planted alongside a fence. Although I get lots of apples every year, I've never tasted even one because some critter beats me to it. I live downslope from Mt. Davidson, so I suspect that it's either a raccoon or rats that access the backyard along the fence line that runs almost directly to the hill. Will the Critter Ridder product you've mentioned before take care of the problem? Other suggestions?

Patricia in San Francisco

Hi Patricia,

The Critter Ridder can not be sprayed on edible crops. It can be sprayed on the fence line. You might consider putting bird netting over the tree when the apples begin to ripen. Animals are leery of getting tangled up in mesh materials. Raccoons have a tendency to snap branches as they feed in fruit trees. If the apples are just chewed away, it’s rats. You may also want to consider baiting or trapping for rats now.

Planting a Japanese maple near the coast. Bad idea??

Dear Garden Guru,

I just saw a picture of a Japanese Maple Tree Orangeola Weeping Dissectum and fell in love with it. I live at Linda Mar in Pacifica, 1 mile east from the beach. I would like to put it in a large pot on my west facing deck. Is this a good idea? Thank you.

Juanita in Pacifica

Hi Juanita,

Japanese Maples are notorious for burning anywhere near the coast. Western exposure to salt-laden ocean breezes will most likely result in an under-performing, brown-leafed disappointment. Take a look around the neighborhood to see if any are growing. If so, and they look O.K., you might try one as long as you can simulate the exposure (east, north-east, etc.).

Growing fruit trees in the Outer Sunset

Dear Garden Guru,

We just bought a place in outer Sunset, pretty good size yard faces West but gets good amount of sun. What kind of fruit trees (would love apple, pear, orange and plum) can we plant and when should we plant them? I don't want them to grow too tall, so dwarf tree? What kind of veggies would do good in this neighborhood? Is it too late to plant this year?

Yuki in San Francisco

Hi Yuki,

You can have all the trees that you desire. If you want a European pear such as Bartlett, they are best planted in, well, pairs. The Asian pear 21st Century is self fertile as are the Santa Rosa Plum and apple varieties Fuji, Granny Smith, Yellow Delicious and Gala. Meyer Lemons do very well too. Choose the UD (Ultra Dwarf) form that grows to 6′- 8′ tall. These can be planted any time of year but the best availability is late winter. Citrus can be planted now. The best orange for you is Trovita, Valencia or Lane Late Navel. Choose a dwarf variety (it must say dwarf next to the variety name).

It is a bit late now for tomatoes, peppers and melons but in the next couple weeks will be the time to start cabbage, cauliflower, broccoli, and Brussels’ sprouts. You can grow any of the greens (lettuce, chard, spinach, kale) year round. You can still get beans and squash in the ground too.

Curious if we have your favorite plant or product in stock? Call one of our locations directly and we'll be happy to check.