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How will the drought affect planting freesia bulbs this year ?

Dear Garden Guru,

How will the drought affect planting freesia bulbs this year ?

Rosey in San Francisco

Hi Rosey,

Freesia are actually fairly drought tolerant, originating in the arid eastern region of South Africa. What they do need is a good winter chill to set the best flowers (usually not a problem for us!). Freesia will actually begin to sprout without irrigation or rain.

Help: White flies!

Dear Garden Guru,

I have an enclosed urban (aka concrete) patio that I’ve spruced up with lots of potted plants - cherry tomatoes, herbs galore, miniature meyer lemon, potato bush, etc. The problem: My garden seems to be infested with white flies. It started on the cherry tomato, but they have spread to the basil, roses, and other plants. I have tried insecticidal soap weekly for months and seem to be losing the battle (nothing like going to get some basil and getting a cloud of white flies all over my hair and body in the process). Help! How can I save my plants from this pest?

Johanna in San Francisco

Hi Johanna,

Whitefly, as you are finding, are very difficult to get rid of.  They are immune to most sprays.  You can control the nymphs that are seen as small oval shapes on the undersides of leaves with a Neem oil spray.  The oil asphyxiates them and will do some good with repelling the adults.  You might consider putting out yellow sticky traps to reduce the populations of the adults as well as incorporate a reflective “mulch” (such as sheets of aluminum foil on the soil surface of the pots).  Your tomatoes and basil will likely stop producing by mid-November. Dispose of the plants rather than compost them.  A hand held vacuum, such as a dust buster can be used to suck the adults off the leaves when they are sluggish in the morning.

Something eating my Abutilon!

Dear Garden Guru,

My abutilon has some sort of pest. The leaves have several holes (all over the place not concentrated in center or edges). Most of the leaves are affected. I have an abutilon right next to the one with the problem and it is unaffected (though a slightly different variety of abutilon). Thoughts on what to do?

David in San Francisco

Hi David,

Sounds like Slug or Snail damage. The best way to be sure is to check at nighttime, as most leaf eating pests are nocturnal. Slugs tend to like moist shady spots, which we assume is where your Abutilon is located.

The solution is to try picking off and discarding any you see, and using Sluggo snail and slug control to eliminate the ones that come out of hiding. This is a non-toxic product that is safe to use around pets. Slugs usually die within 4 to 6 days after eating it. Sluggo lasts about 3 to 4 weeks and then breaks down as an Iron fertilizer. Reapply as needed.


Dear Garden Guru,

I have had a Brugmansia Charles Grimaldi for at least 7 years and have had numerous problems with it such as aphids, snails. etc. I have told myself that I am not giving up on the plant, but it has never flowered. Is there such a thing as a male and female tree and do you think that I am missing one of those? Help!

Julie in San Francisco

Hi Julie,

Brugmansia are very much dependent on daylight to trigger blooming. They will start to set buds when  the days start becoming shorter and nights become cooler, usually late August to September.  Also Brumansia stalks must become forked before they produce flowers. Growth below the fork is juvenile or vegetative.  Growth above the fork is considered adult or flowering.  Have you cut the plant back so that there is no fork?  Are all the stems and trunks on the plant still straight?  The plant does not require male and female.

Aphids on succulents: help!

Dear Garden Guru,

What is the best way to get rid of aphids from my succulents? They are only damaging a couple varieties but the ones damaged are pretty bad. Thanks

Hunter in San Francisco

Hi Hunter,

You can control the aphids with Bonide All Seasons Oil. This non-toxic oil spray will smother both eggs and adults. Water your plants prior to spraying and apply when temperatures are 75 degrees or less.  Thank you for choosing to garden with us!

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.

When should I start planting?

Dear Garden Guru,

Recently I moved from San Bruno to San Carlos. When is the ideal time to plant my garden seedlings? I wonder if it too early to start my garden (particularly tomatoes)?

Mara in San Carlos

Hi Mara,

You can start your gardening projects right now. This would include planting your seedling vegetables (peas, greens, strawberries, cabbages, kales, beets, carrots, onions, spinach), as well as the tomatoes, beans and squashes and basil. All Sloat Garden Centers now have the most varied vegetable selection of the season. As you plant during this cool spring weather, please keep in mind that tomatoes need consistent warmth. If you want to plant tomatoes now, you will need to protect them from cold nights.

Growing salad greens

Dear Garden Guru,

I'd like to know the best way to grow salad greens throughout the summer. Can I plant them in succession so that I'll have 4 months of salad? Also, I live in a foggy pocket of the east bay - does that make a difference?

Beth in El Cerrito

Hi Beth,

The easiest way to get your summer greens going is to start with pre started cell or jumbo packs. You can always supplement with a sowing of seed.

Should you opt for seeding only, be sure that you do not bury the seeds too
deeply. The best results with lettuces and greens is to prepare the bed (be
sure to mix in Loam Builder and Agricultural lime) so the soil is nice and crumbly. Sprinkle the seeds on top of the soil and then water. The seeds will settle into the soil at the right depth. Carrots and Lettuces need UV light to germinate! You do not need to pull up whole heads, it is better to cut the plants off about an inch above the soil. The greens will quickly regrow. Feed with a liquid fertilizer such as Maxsea All Purpose after cutting. Should you want to pull up whole heads or the plants begin to slow down coming back, you can resow or plant every 3-4 weeks to keep a fresh crop coming. The fact that you live in a cool, foggy location is actually a blessing for growing greens. They do not like it hot. We actually recommend planting in part shade in our hotter areas.

Tomato plants

Dear Garden Guru,

My tomato plants always look beautiful when I get them in the ground. I water and fertilize and then right after the plants flower they turn yellow and spindly and they don't fruit very well. What am I doing wrong?

Liz in San Bruno

Hi Liz,

Yellow and spindly tomatoes don’t fruit that well do they? Believe it or
not, I suspect that you are loving your plants too much. Over watering
tomatoes will wash away all the nutrients you so lovingly applied, it also
reduces needed oxygen in root zone and makes the plant susceptible to
disease. Your plants should be deep watered 2 to 3 times a week. If the
plant is seen wilting in the middle of the day, ignore it. Tomatoes will
close their stomas in the heat of the day to prevent water loss by
transpiration. They will perk right back up by late afternoon. If the plants
look droopy in the morning, they need water. Too shady a location will also
cause plants to be spindly but you usually see that effect immediately. If
the leaves are showing some signs of browning, your plants may have
Verticillium or Fusarium wilt. These are soil borne pathogens and there is
no chemical control available. Warm and humid conditions will hasten the
onset of wilt. It is highly recommended that you plant tomatoes labeled
with “VF” (Verticillium/Fusarium) on the label as these are resistant
varieties. Should there be an “N”, that means resistant to root knot
nematodes. Hope this helps for this year’s crop!

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.