Ask the Garden Guru

Rose Pruning

Dear Garden Guru,

I'm pruning my roses. Some are very tall. Is it true that if a branch of a rose bush has no thorns, it is 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

Hi 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.

Do bulbs need to be refrigerated?

Dear Garden Guru,

I have dozens of bulbs for fall planting. I've learned I have to refrigerate the crocus, hyacinth and tulip bulbs, but I'm getting mixed messages on refrigerating daffodils in Northern California. Do daffodil bulbs need to be refrigerated in this area? Anything else I should or shouldn't refrigerate? (I know about not keeping fruits in the fridge with the bulbs.) Thanks!

Susannah in Kentfield

Hi Susannah,

You do not need to refrigerate Daffodils or Narcissus. Some people keep Paperwhite Narcissus in the refrigerator to “stall” sprouting so they can force the bulbs over a longer period of time. This is probably where you are getting a mixed message. While not necessary, some people like to chill their Freesias – it seems to make the stems sturdier.

Plants for sandy soil

Dear Garden Guru,

What plants would you suggest for sandy soil in the inner sunset?

Pat in San Francisco

Hi Pat,

Sandy soil and a tad of salt wind, nothing like it!

Perennials that work are: Lantana, Euphorbia, Centranthus, Erigeron, Santolina, Phormium, Pelargonium (Martha Washington and Zonal Geranium), Limonium perezii (Sea Lavender), Armeria, Artemesia, Agapanthus, Echium, Lavender and Argyranthemum (Marguerite Daisy)

Suitable shrubs are: Rosemary, Westringia, Pittosporum tobira and Pittosporum tobira Wheelers Dwarf, Coprosma, Cistus, Hebe, Escallonia, Rhus integrifolia (Lemonade Berry), Melaleuca, Leptospermum, Correa and Dodonaea.

Trees are: Metrosideros, Arbutus, Myoporum laetum standard. Eucalyptus will also work but you don’t need the mess.

Fall Fertilizer questions

Dear Garden Guru,

What is the best fall fertilizer to use for everything from fruit trees, roses, to flowers? How often should I fertilize over the winter?

Gary in San Anselmo

Hi Gary,

Fall fertilizers are not high in nitrogen. Historically, the use of 0-10-10 or Alfalfa meal has been recommended to provide a boost to plant’s immune system to combat the ravages of coming cold weather and subsequent fungal diseases. The best practice after this is mulching or top dressing with a manure or Forest Mulch Plus (the Plus is chicken doo). Do not apply a mulch to fruit trees as this will hold excess moisture in the ground around the tree which is harmful. Don’t feed plants over the winter as this encourages new growth that can be killed by frosts. The only exception would be annual flowers such as primrose, pansies and cyclamen which are actively growing in winter.

Planning an herb garden

Dear Garden Guru,

I am envisioning a small, kidney shaped herb garden right on our front lawn. I'm thinking about a raised bed, nothing too complicated, probably borders of some kind of stone or hardscape. What sort of herbs grow best in our climate? And can you offer any process insight in design?

Eric in San Francisco

Hi Eric,

Herbs that do well in your area are: Rosemary, Spanish Lavender, sage, parsley, Santolina, chive, and marjoram or oregano. Thyme and basil can be fickle. You may want to reconsider the kidney bean shape. A square or rectangle is more conducive to the classic herb knot and easier to work with. Choose plants that contrast in foliage color. After the size of the bed is decided, graph paper and colored pencils are very helpful. Each square could represent 1/4 ‘ so consider planting two 3″ pots per foot. Use a different colored pencil for each herb. In other words, 4 squares in a row would be colored the same. It might be worth looking at some of the DIY and HGTV links or calling our Design Department to schedule a consultation. The number is 388-3754.

Fruit Tree Planting in Winter

Dear Garden Guru,

I would like to plant fruit trees this winter but I live very close to the ocean, with lots of summer fog. Which fruit trees would you recommend for my microclimate?

Melissa in San Francisco

Hi Melissa,

For your foggy, coastal conditions consider Santa Rosa plum, Meyer Lemon, Persimmon, Asian Pear 21st Century, and Apricot.

For something more exotic, the Pineapple guava, Feijoa sellowiana, will work. You could also consider Blueberries!  Many of these will be available in January or by special order later in the season.

Lemon and herb recommendations for a SF Mission garden

Dear Garden Guru,

We live in the sunny but windy Mission district. Can you recommend a lemon tree and herbs that will work in this micro-climate? Thank you!

Donna in San Francisco

Hi Donna,

The Meyer lemon does very well in San Francisco.  The Eureka lemon will also grow but gives only one crop a year where the Meyer is known to produce almost year-round.  Herbs that will do in your neighborhood are rosemary, oregano, marjoram, thyme, and sage. These are woody plants and are not thirsty.  You can grow parsley, chervil, and savory but these “soft” herbs will require more water.

Growing vegetables this spring...

Dear Garden Guru,

I want to start growing vegetables, herbs and possibly fruit and I'm thinking of mainly using a green house since the weather in San Francisco can be unpredictable. Will the plants do well in a greenhouse and what fruits do well in San Francisco? Also, I read that I can grow potatoes from a potato I already have in my kitchen - will that way work or is it better to start from a seed? Thank you!

Rebecca in San Francisco

Hi Rebecca,

Your vegetables and herbs will do fine in a greenhouse. If the greenhouse will be completely enclosed (closed doors and windows), the flowering vegetables will not have access to pollinators. It will be necessary for you to act as the bee. This can be done by gently shaking the plants once in flower (tomatoes and peppers) or transferring pollen with a fine artist’s paint brush (squash, tomatoes, peppers). As for fruits, you can plant strawberries, apple, pear, southern highbush blueberries, persimmon, and plum with the greatest success.

As for potatoes, it is best to start from a “seed” potato. Most potatoes from the grocery have been treated to prevent sprouting. Organically grown, new potatoes can sometimes be used.

What do I grow in my container garden during the winter months?

Dear Garden Guru,

I'm from the midwest, where the winter snow prevents people from growing year round. Now that I'm in San Francisco, I have no idea what to grow in my container garden in the winter months. Any suggestions for what do on my patio from October-March would be most helpful to this midwest gardener!

Courtney in San Francisco

Hi Courtney,

You are in for a treat because the fall/early spring gardens are fun.  Annuals that are available in September are stock, pansy and viola, snapdragons, paludosum daisy, and Iceland poppy.  The snapdragons and poppy will look there best in early spring  but are best established in the fall.  The others will give you color even in the winter months.  Arriving in October are primrose, ornamental cabbage and kale, and Cyclamen.

If you want to grow some edibles,  lettuces, peas, broccoli, kale, Brussels’s sprouts and chard are available as starts, or you can start from seed.  Best from seed are onions, carrots, beets and other root vegetables.  Herbs such as parsley, thyme, sage and rosemary can be planted.  Of course, our full selection of spring flowering bulbs are available in September.  Bulbs over planted with violas work very nicely in pots.  October is also the best time to plant sweet peas, foxglove, and California poppy.  There are also fall garden mums!   There’s a reason this is such a popular state.

Fog-tolerant herbs, fruits, veggies, and flowers that attract bees & hummingbirds

Dear Garden Guru,

Can you recommend a list of fog/Mediterranean climate tolerant herbs, fruits, veggies, and flowers (which attracts bees and hummingbirds)? Any guidance will be much appreciated.

Wayne in San Francisco

Hi Wayne,

The first tip is to take care of the soil. Don’t skip on the amendments that will help retain moisture and offer nutrition. Water regularly, especially the flowers and vegetables. Choose organic fertilizers that will not harm the beneficial soil organisms that help your plants’ root systems by improving nutrient uptake and guarding against disease. Actinovate is a wonderful supplement for any new garden plant.

Vegetables: peas, lettuces, chard, beets, cabbages, broccoli, mustard, spinach, carrots, radishes, kohlrabi, arugula (actually all your greens), in the summer- cherry tomatoes too. Herbs- parsley, cilantro, rosemary, chervil, savory, sage, thyme, oregano, marjoram

Fruits: raspberries, southern highbush blueberries, apples, pears, strawberries, loquat, pineapple guava, lemon, kumquat, Trovita orange

Flowers that attract beneficials and pollinators- white alyssum, cosmos, achillea, agastache, tulbaghia, Oenothera, Eriogonum (Buckwheat), Erigeron, Dianthus

Hummingbirds:– Abutilon, Fuchsia, Agastache, Salvia greggii, Salvia clevelandii, Nasturtium, Delphinium

There is so much more, but this will get you started.

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