Ask the Garden Guru
Garden Guru Topics
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.
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.
Fall Foliage in the Bay Area
Dear Garden Guru,
Being from upstate New York, I really miss the fall colors. I recently traveled to Portland and noticed some trees there were alive with fall foliage. Can I grow such trees and enjoy the same bright colors every fall here in S.F.? And, if so, what are the bright yellow, red, reddish pink and orange trees I see. Also, what vine grows up the trees and turns red each fall?
Lee in San Francisco
Hi Lee,
San Francisco has a very mild climate and the degree of temperature fluctuation from night to day is very small. All those brightly colored trees require a change in weather (colder than what we have) to start the coloring process (along with a bunch of other factors that affect their biochemistry). Those multi-hued trees you see are Chinese Pistache and they require the least amount of chill to get going. Ornamental Pear and Liquidamber are two other trees for you to consider. Our customer service team members can help find them for you at any Sloat location.
The vine you mention is Boston Ivy. There are two types available Partheocissus tricuspidata (3 lobed leaves-the classic) and Parthenocissus quinquefolia (5 lobed leaves). Both will change color in San Francisco, albeit later than the surrounding counties.
I hope this helps you find some fall colors.
Waterwise Privacy Screens
Dear Garden Guru,
I am looking for a waterwise, evergreen shrub that will grow 10ft tall to provide a privacy screen. Any suggestions?
Carin in Novato
Hi Carin,
Hello! Good candidates for your purpose are:
- Podocarpus (all species and varieties: gracillior, macrophyllus, Icee Blue)
- Dodonaea ‘Atropurpurea’, the Hopseed
- Rhamnus alaternus and Rhamnus John Edwards
- Pittosporum tenuifolium
Fungus gnats on my ficus
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
Hi 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.
Help with Gophers!
Dear Garden Guru,
Gophers have invaded our yard – there are holes everywhere! How does one get rid of them safely and not harm other animals and birds?
Deborah in Pacifica
Hi Deborah,
Start by using a repellent like Bonide Mole Max (it also works for gophers ). This is a castor oil-based repellent that is not harmful to animals or birds. Take extra care to apply more heavily around holes. This granular formula is easier to apply than a liquid spray. Apply the repellent gradually towards the direction you want them to leave the property, in other words, leave them a way to get out. Applying the repellent to the whole space at once will just “trap” them there. If it is really very bad, you might consider a gopher removal/trapping service such as Smith’s Pest Management which focuses on trapping over poisoning.
Additional notes:
- Plants that tend to be deer resistant also have less appeal to gophers (See the plant list).
- Nothing is truly gopher “proof” and you may need to plant in gopher cages.
- Here’s a link to common questions about gophers: http://www.sloatgardens.com/gophers.htm
Squirrels in Raised Beds
Dear Garden Guru,
I have raised planter beds with steel mesh screens to keep moles and voles away, but squirrels got into my vegetable garden last summer. Do you suggest tall plant protectors that can cover a fully grown tomato plant?
Mark in Pleasant Hill
Hi Mark,
We carry larger tomato cages that will support large plants but the openings would still provide access to the ripe fruit. Some gardeners have used plastic bird netting wrapped around and over a caged tomato to protect ripening fruit from various varmints.
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.
Squirrel deterrents
Dear Garden Guru,
Squirrels are destroying my vegetables and flowers. Does peppermint oil spray on leaves deter them?
Robin in Pleasant Hill
Hi Robin,
Hello Robin,
Yes, peppermint oil can be effective in deterring squirrels. We carry a product from Messina specifically for squirrels called Squirrel Stopper. The ingredients are putrefied egg, and oils of mint, rosemary, and cinnamon. It can be used on hard surfaces and perimeters as well as plants. We don’t recommend spraying this product on edible plant parts — it’s best used as a barrier spray.
Fungus Gnats!
Dear Garden Guru,
I enjoy a window herb garden in my kitchen and every year we have a few gnats. This year there were so many more. Any advice on a safe way to address them in my home? Thanks for your help.
Claude and Ruth in the East Bay
Hi Claude and Ruth,
Curious if we have your favorite plant or product in stock? Call one of our locations directly and we'll be happy to check.