template_images/title_gardenguru.gifFlowering Plants & Shrubs

Pruning a Forsythia
Q: Dear Garden Guru,

I recently purchased a Forsythia from your store...it's in bloom right now and looks just awesome! I'm just wondering when is the best time to prune it? How much should I prune?

Thanks!
- Daniel in San Francisco
   
A: Dear Daniel,

You can always prune some of your Forsythia right before it blooms so that you can have flowering stems in the house. Forsythia only needs pruning to control height and or to keep it in shape. The best time to prune is after flowering in late spring (May or early June). The flower buds for next year are formed by mid-summer; pruning too late will sacrifice next year’s blooms.

Thanks for choosing to garden with us.
The Garden Guru
 
Why wont my rhododendron flower?
Q: Dear Garden Guru,

I planted a rhododendron over five years ago in my garden near the Sunset district. It has never flowered. What am I doing wrong? Thanks in advance for your reply.

- Evelyn in San Francisco
   
A: Dear Evelyn,

I fear that your Rhododendron may be in too shady a location. Rhododendrons do best in part sun or full morning sun. If they receive too little light the buds turn to leaf. You may want to consider moving it this coming Fall when it goes dormant. To do so now may stress the plant considerably.

Thanks for choosing to garden with us.
The Garden Guru
 
Repelling Skunks
Q: Dear Garden Guru,

Do you know of any plants that would help to repel skunks? There are a lot of them in my neighborhood, and I'd like for my dog to not get sprayed...

- Jennifer in San Francisco


   
A: Dear Jennifer,

I know of no plants that will deter skunks. We do carry a product called Critter Ridder from Havahart that has proven to be a good repellent for the urban, wild animals. It is granular so it’s easy to apply. I would try sprinkling it around the perimeter of your space and for sure, by garages or garbage cans. Try to keep pet foods removed from outdoor areas at night if applicable.

Thanks for choosing to garden with us.
The Garden Guru
 
Wisteria Care
Q: Dear Garden Guru,

I have 2 tall Wisteria vines growing up the front of my house. They are at least 50 years old. Each year they grow thick lush leaves but when they flower in the spring there are only a few flowers which last for a few weeks. Is there any to encourage more flowers and less leaves?

- Jerry in San Francisco
   
A: Dear Jerry,

Are you pruning these vines back hard each year? Wisteria flower on old wood and you may be cutting away flower buds. When pruning Wisteria, the young, loopy growth can be removed but the flowering spurs on older, 2 year wood should be kept. The flowering spurs are shorter branchlets with visible dark brown flower buds that resemble little almonds.  Wisteria do best with little or no feeding. If they are given too much nitrogen, they produce more foliage and fewer flowers.

Thanks for choosing to garden with us.
The Garden Guru
 
Apple Trees
Q: Dear Garden Guru,

I have a 40 year old golden delicious apple tree up to two years ago lots of fruit. Last year and this has grey moldy spots on the trunk and limbs and white fuzz at the tips and leaves. causing the leaves to fall and bearing the limbs. I tried to spray with soap and blight spray but, it is higher than the two story house and not getting any better Should I cut it down and start all over??

- Sara in San Francisco
   
A: Dear Sara,

What you describe on the bark of the tree and tips of branches is lichen. This will not kill the tree but usually invades very old bark. The best way to control this fungi/algae symbiosis is to spray the bark of the tree with Kop R Spray. This spray will also control powdery mildew which creates a white coating on leaves and causes them to turn brown and die. When powdery mildew is really prevalent, there will be much leaf drop. Less leaves means less energy to carry and bear fruits. I would recommend possibly having the tree reduced in height. It is advisable to begin spraying now, again in February and once again when the flower buds begin to swell. I would give your older tree the benefit of the doubt for a couple more years. Consider that 2006 was the wettest year on record and a horrible fruit production year and last year was very very dry, equally stressful. 

Thanks for choosing to garden with us.
The Garden Guru
 
Shade Plants
Q: Dear Garden Guru,

Hello, I am creating a plan for my front court yard. i have a large Magnolia tree that blocks 85% of the sun. Could you please suggest some hearty shade plants/flowers? I live on the water and there is much salt air. Thanks!

- Joe in Novato
   
A: Dear Joe,

Shrubs that will work in that shady spot are Viburnum tinus, Pittosporum tobira (which also comes as a variegated variety), Aucuba, Boxwood, Camellia, Fatsia, Hydrangea and Nandina.

Perennials and flowers that will thrive are Calla Lily, Fuchsia, Heuchera, Lamium, Liriope, Foxglove, Campanula, and Hellebore.

Some annual flowers that will work are Impatiens, Coleus and Primrose.

Thanks for choosing to garden with us.
The Garden Guru
 
Rose Pruning
Q: Dear Garden Guru,

I'm pruning my roses. Some a very tall. Is it true that if a branch of a rose bush has no thorns, it's a sucker? I've tried to get down to the bottom of the bush to see if the branch is coming from the base of the bush or from the ground. I can't always identify so I was wondering if the absence of thorns makes a difference. Any help would be appreciated. THANKS!!

- Lorraine in Walnut Creek
   
A: Dear Lorraine,

Unfortunately, the lack of thorns does not indicate whether you have a sucker or a cane.  Many rose bushes will throw almost thornless canes occasionally that produce an umbel of flowers. They are difficult to prune in that they don't always have a well oriented leaf bud scar to make a cut above.  You really do have to see if the origin is coming from beneath the bud union or the root zone. These thornless canes are often skinnier than there thorny sisters which makes it even harder to tell.  You won't be hurting anything if you feel you must remove it just to be sure.

Thanks for choosing to garden with us.
The Garden Guru
 
Toyon
Q: Dear Garden Guru,

I have had a toyon shrub for 4 years. It has never flowered or developed berries and I have always assumed this is because it doesn't get enough sun. {I am in the Twin Peaks area} However this spring we took down a tree and the toyon received significantly more sun and it did flower heavily but still no berries. Do you think berries are a lost cause on this shrub?

- Charlene in San Francisco
   
A: Dear Charlene,

I would not give up hope on your Toyon. Getting it more sun so it would bloom was half the battle. I believe the problem was a lack of pollinators. The freeze we had last winter killed many beneficial insects.  As well, the bee population has been compromised by one disaster or another for close to 10 years now.  It is also possible that the young berries aborted early in the season right after flowering.  We had so little rain this past season, many unirrigated plants set poor fruit crops.

I hope this helps. 

Thanks for choosing to garden with us.
The Garden Guru
 
Pacific Iris and Brugmansia/Datura
Q: Dear Garden Guru,

A few years ago Sloat offered special varietes of Pacific Coast Iris (different colors, etc) Are they available this year? If not, what are the botanical names? Question #2 Do brugmansia and datura have different cultural requirements? What are they? Thanks so much!

- Grace in San Rafael
   
A: Dear Grace,

Sloat will indeed have many varieties of Pacific Iris. The greatest selection is to be had in March. There are so many named varieties that it would be difficult to list them all. Most of the stores still have a few 1g cans but they are dormant right now. As far as the difference between Brugmansia and Datura, the cultural requirements are very different. Brugmansia require a sheltered location from wind and hot sun. They grow naturally under the high canopy of the Amazon rainforest, so a part sun location suits them best inland. They will take full sun on the coast, provided they are out of the wind. Give them regular water and composted soil.  Datura are  desert loving plants that require fast draining soil. They will take more sun and less watering.

I hope this helps. 

Thanks for choosing to garden with us.
The Garden Guru
 
Dalia Tubers
Q: Dear Garden Guru,

I have dahlia tubers that I have dug up since I saw that some were rotting but what about my dahlia hybrid that I've grown from seeds and the species bishops children. they're all dried up, do I just keep them in their pots till next summer when they'll come back?

- Margarita in Daly City
   
A: Dear Margarita,

Thank you for your question. You may want to lift the small tubers from the pots as well and store them in paper bags with some peat moss. This will allow you to replant them in fresh potting soil next spring. If you choose to leave them in the pots, store them dry until February when you can rewet them. I have had hybrid Dahlias last for years by doing both.

I hope this helps. As always, feel free to visit any of our Sloat locations for more expert advice.

Thanks for choosing to garden with us.
The Garden Guru
 
Pyracantha
Q: Dear Garden Guru,

Can you please tell me what plant is in the December red pottery picture. I inheritedone of these plants when I bought this house and use the berries as Christmas decoration, but if it is an invasive, I would like to get rid of it. Also, the berries dry out quickly when cut. Any ideas on how to keep them looking better for longer?

- Barb in Oakland
   
A: Dear Barb,

The plant pictured was a Pyracantha. They are not considered invasive. Once branches have been cut, it is very difficult to keep them looking fresh for long if they are not in water.  Spraying your cut foliage and berry sprays with Cloud Cover will help seal in the moisture. Floral foam will also hold water. Try making arrangements on a plate or saucer. The greenery stuck in the foam conceals your plate and you can keep adding water as needed.

Thanks for choosing to garden with us.
The Garden Guru
 
Caring for Fuchsias
Q: Dear Garden Guru,

I'm somewhat worried about one of the potted Fuchsias I have. The one I'm worried about gets watered every day for about 10 minutes. About a month ago this plant was growing very well, then all of a sudden it's lost all of it's leaves and buds, have I killed this plant? I also need to know when is the best time to prune Fuchsias?

- Ritch in Hayward
   
A: Dear Ritch,

Is it that your Fuchsia still has no leaves after a month? And you are still watering it everyday? If this is the case, I think that your Fuchsia may be dead. Watering everyday, especially when the weather is hot will cause root rot. This is probably what happened to your plant initially. If you scrape the bark on the main stem of the plant, you should see some green, if the plant is still viable. If you see green, cut the plant back now by 60-80% and stop watering until it begins to grow again. If you don't see any sprouting by the end of 3 weeks, the plant will most likely not come back. As far as the best time to prune healthy Fuchsias, we suggest late February.

Thanks for choosing to garden with us.
The Garden Guru
 
Mildew on Begonias
Q: Dear Garden Guru,

I've had a Semperflorens begonia for many years that has been continuously beautiful and free of pests. This year it has become infected with mildew. What's the best, least toxic remedy?

- Debra in San Francisco
   
A: Dear Debra,

Begonias get mildew when the humidity increases and we have cool nights followed by warm days. The easiest and safest way to get rid of the mildew is to spray with Serenade. This is a non toxic (except to funguses) spray certified by OMNI. It is safe to use on Begonias and will not burn leaves.

Thanks for choosing to garden with us.
The Garden Guru
 
Moving a lilac tree
Q: Dear Garden Guru,

We have a large lilac already in our back yard, but we are re-designing the garden in a modern/asian style. I would like to move the tree from the center of the garden to a place across the yard that is by the steps and therefore not the first thing you see. It will still get about the same light. Will it die if I try and move it? What steps can I take to ensure it's health and how do I dig out all the roots? thank you!

- Stephanie in San Francisco
   
A: Dear Stephanie,

You would be best waiting until late fall to transplant. Follow the steps below.
  1. Ensure that the plant has been watered in the previous 72 hours.
  2. The top growth of the plant should be pruned back at least 25% to lessen the stress on the soon-to-be damaged root mass.
  3. Have the new hole dug and prepared with organic material and some agricultural lime.
  4. Begin to dig around the plant (24-36" away form the trunk) with the goal of creating a root ball 18-24" across and 24-30" deep.
  5. You will need two people with shovels to gently work the root ball loose and surround it with an old sheet or burlap tote.
  6. Once wrapped, the plant can be moved to the new hole and planted at the same depth, adding Sloat Forest Mulch Plus, Agricultural Lime and Sure Start fertilizer
  7. Water heavily and wait. All remaining leaves may drop off but that is OK as long as the branches and stems remain firm and don't turn black.
  8. Come spring you should see a surge of growth. Don't be surprised if the plant does not bloom that first year after transplanting.
Thanks for choosing to garden with us.
The Garden Guru
 
Rose Transplanting
Q: Dear Garden Guru,

We would like to transplant our roses. They are in an area that does not appear to be the best and the leaves are being eaten by something. When is the safest time to move them and what do we need to do to make sure the move is a successful one? Thanks for your help.

- Shauna in Pacifica
   
A: Dear Shauna,

If you can wait, the best time to transplant your roses is late November or early December. This is the time that they begin their dormancy. You can do all your pruning before you move them and treat them like a bareroot, meaning you won't have to get the entire rootball. It is best to have the holes already prepared, usually about 1' deep and 2' wide. You will want to amend your soil with organic matter such as EB Stone Rose Mix. Additional Alfalfa meal and or bone meal at the bottom of the hole will help the plants "bounce back" rapidly when the weather begins to warm again in February.

As for holes in the leaves, as a general rule, if the middle of the leaves are being eaten it is slugs or snails. If the outer edges of the leaves are being chewed, it is caterpillars.  At all of our Sloat locations near you (San Bruno - 675 El Camino Real; 2700 Sloat Blvd, San Francisco) we have products to help fight these insects/bugs. Of course, you can also try plucking them off your plants early in the evening or a bit later with a flashlight too!

I hope this helps steer you in the right direction.  And as always, visit our stores for more expert guidance.

Thanks for choosing to garden with us.
The Garden Guru
 
Anigozanthos Care
Q:

Dear Guru,

I've purchased several anigozanthos (Kangaroo Paw) and after a beautiful bloom this summer, they've all turned brown, dry and look dead. Is this normal? Do I merely cut them back and wait for Spring? Last year I threw all of them away as I thought they were dead, but maybe I've been mistaken. Please advise. Thank you,

- Karen in San Francisco
   
A: Dear Karen,

Thanks very much for your question. It is normal for the flowering stalks of Anigozanthos to turn brown and dry up towards the end of summer. The leaves, however, should still be green. If the whole plant has turned brown, it may be that it was over watered or in soil that did not drain well or that it was too dry. They also do not like fertilizer with Phosphorous. Here is a check list to keep the plants alive:
  1. Plant in a sunny location. If you live where there is frost, plant under the eave of a house or high tree canopy
  2. Give excellent drainage (lots of compost or sand/gravel)
  3. Where it is dry in the summer, they need regular water
  4. Do not feed heavily and avoid Phosphorous (middle number)
  5. After the flowers have died, remove the stalks and leaves to almost ground level. Each "fan" of leaves only flowers once. Be careful not to cut or damage new fans that are forming. These will flower next year.
I hope this helps. As always feel free to visit any of our stores for more expert advice!

Thanks for choosing to garden with us.
The Garden Guru
 
Feeding azaleas, camellias and hydrangeas
Q: Dear Garden Guru,

I feed many acid plants [azalea, camellia, and hydrangeas]. Is the same acid-based food good for magnolias and hibiscus?

- James in San Francisco
   
A: Dear Jaime,

Thanks for your question. With regards to Magnolias, they generally like neutral or SLIGHTLY acidic soil. So, yes, you can use your acid food for them, but you may want to dilute it a bit from regular doses, and don't use it as often as the instructions say for true acid-loving plants.

As for Hibiscus, I've referenced some instructions from the following website, as they are excellent. www.hiddenvalleyhibiscus.com/care/feeding.htm

"Hibiscus produce their most and best flowers with a fertilizer high in potassium - that is the third or last number in the formulas often given on fertilizer containers. Sometimes, people are tempted to use the "super bloom" type formulas which are very high in phosphorus - the middle number of the formula. This is NOT GOOD for hibiscus as research has shown that high phosphorus can prevent hibiscus from absorbing other nutrients it needs. These types of fertilizers may be sprayed on the leaves of the plant as a "foliar feeding" but should not be added to the pot.

If you use a local brand, it's good to check that the plant food is complete - that it contains "minors" which are small amounts of minerals that hibiscus also need. They will be listed on the side of the container. Look for ingredients like copper and iron. Be sure to follow the directions that come with the package of fertilizer. Hibiscus like to be fed small amounts often rather than large amounts occasionally. If you can hook up your water hose to a proportioner or fertilizer injector, you can water and feed easily at the same time. Otherwise mix your water and water soluble plant food in a container and pour enough of the solution into each pot so that some comes out the bottom of the pot. Fertilize when the pots are moist, not when they are dry. Use plenty of plant food in the summer and less during the winter."

At your local Sloat Garden Center, you will find that we carry a Hibiscus specific food that does meet these suggested requirements. And that is what I would recommend for success with growing yours.

Thanks for choosing to garden with us.
The Garden Guru