Garden questions


tomatojuliet.jpgTomato 'Juliet' is prolific
This page has been created as a question and answer page for anyone with garden and landscape questions. Don Shor will check this page periodically and answer general questions about gardening that anyone may have. Comments from here may also become part to the "Davis Garden Show" radio program hosted by Don Shor and Lois Richter on KDRT. Other plant experts and gardeners should feel free to contribute! (Please sign your comments.)
Don't forget to check out the resource links at the Gardening page.

Mystery plants to ID
ArbFlower2ID.jpgWhat's this vine? (at Arb)

Ask your garden questions here!

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2010-03-31 19:46:28   No questions yet, but I love this page already. —TomGarberson

2010-04-02 12:28:44   Just to answer the most common question we're getting right now: It is TOO COLD to plant tomatoes, peppers, and eggplant in the ground! Plant tomatoes when the soil temperature is minimum 60F, which is usually when the night temperature is consistently above 50F. Plant peppers and eggplants when the soil temperature is consistently 70F, which is usually when the night temperature is consistently above 55F. For updates on soil and night temperatures, check [WWW]

2010-04-02 12:41:01   I thought I cut my roses quite a bit in January, but they are already grown back to where they were! Is it too soon to cut them again? And how much can I cut them without damaging the bush? —CovertProfessor

2010-04-02 13:05:48   When building a set of retaining wall for a raised garden (typical small square plot with a lowered cross walk), are there any materials to avoid using for the walls? I'm concerned about chemicals that might leach into the soil from treated wood or a solid capped concrete block wall might retain too much water at the edges. Or does it not really matter? —JabberWokky

2010-04-04 23:02:59   Looking for a ground-covering plant that doesn't need a lot of sunlight. My parents are in the Bay Area, in one of the valleys in the East Bay. There's several different types of taller trees, and a lot of shade between those and the house, so a lot of smaller plants don't do so well. Moss unfortunately does very well. Most of the soil isn't that great, high in clay. I've seen plants that look generically shiny and are very leafy like ivy, that spread out to cover all the ground. Any recommendations? —EdWins

2010-04-05 08:10:57   I compost my chicken manure with pine shavings from their coop. I have been told pine shavings are very acidic, I have also been told Davis soil is alkaline. Do you think those pine shavings will create too much acidity? —DagonJones

2010-04-28 14:25:00   I live in Oakland, and just started listening to your radio show via podcast, and want to thank you for all the good info! Thanks to you, my tomatoes aren't in the ground yet :) I have inherited a gardening problem that I want to ask you about: a passionflower vine in a neighbor's yard, planted long before I came to the neighborhood. The neighbors do minimal yard maintenance, and it has taken over their yard, their citrus tree, and 3 other yards including mine. It has well established roots and runners under deep concrete, over fences, and basically everywhere. I am a beginning gardener, and the majority of the time I spend in my garden is devoted to taming this behemoth so it doesn't cover and kill all my plants. I don't consider this very fun or rewarding, and somehow, I suspect that I'd really love gardening if I had time to do things other than ripping out vines. I read somewhere that the only way to control passion flower vine is have a good freeze, but I don't expect that anytime soon in Oakland. Is there any way to get rid of this passionate pest? —siren202020

2010-04-30 22:42:41 We also discussed this on our 4/29 broadcast on KDRT. Thanks for the question! —DonShor

2010-05-24 17:36:18   In looking for a US zone map, I was surprised to come across many sites that dismiss with distain the USDA zone guidelines as being utterly useless. While it does make sense to regard them as guidelines rather than some kind of law with engineering precision, I didn't know there was such venom directed against them (several of the sites were nurseries). Is this view common among today's gardeners, or is this a function of either the internet (where dismissing commonly held beliefs is often seen as somehow sophisticated), or nurseries (which might not want people to limit themselves in what they buy)? —JabberWokky

Sunset: [WWW]
There is an excellent overview of some of the problems with the USDA zones at: [WWW]

2010-05-25 21:21:30   I've got a pretty loose potting soil in my homemade inverted tomato pot, and water seeps through it pretty quick. Any general advice on various tools to simplify the watering of pots? My folks use some little plastic widgets you can stick a plastic water bottle into upside down that will regulate the water flow. I know there are also those gel things that'll soak up water and keep things moist for a bit. I'm used to watering near-daily, but it'd be nice to have a backup just in case I forget or get lazy. —TomGarberson

2010-08-01 19:31:58   What is the best way to start a new plant from a larger existing tree or shrub. I have some hormone (auxin I think) that is supposed to work as a root starter. I have an existing flowering maple and lavender. I think the lavender is a French variety with the long thin stalk like in the west beds in front of Bistro 33 —DagonJones

What do you mean by softwood cuttings? what part of the plant is that? by growing shoot tip do you mean the top of the plant? —DagonJones

2010-08-06 11:06:29   I gave up on my garden this year when I realized that all I was doing was making a glorified animal feeder. EVERY time I saw a hint of a fruit it got eaten by something that wasn't me. Squirrels? Birds? I don't know. I ate one strawberry that was terribly under-ripe just because I wanted to snag it before the animals did. What can I do to avoid this? My plants are all in pots right now but by next year I hope to have my planter box (about 6 feet square) full of dirt and plant in there instead. I know chicken wire is an option but that wouldn't protect against birds and since the plants/box are right next to a fence it would probably just trap squirrels INSIDE there with the plants. Maybe I need one of those laser thingies they have protecting expensive stuff in museums in movies. —JenniferCook

2010-09-04 20:14:01   My parents have a fruit tree they bought and planted sometime last year: "Fuyu Persimmon (Jiro)" and it says "rootstock: Lotus Persimmon." They also planted a Meyer lemon tree and some other fruit tree in the same area/row. All three trees took, but the persimmon tree is growing a bit funny. It was maybe 6 feet tall when they got it and thin. It's now over 10 feet tall, but still super thin. It's got leaves and little branches almost along the whole length, but we're concerned that it's going to outgrow the wood its propped/lashed to and fall over. Is there something they should be doing differently? Some way to make it thicken/strengthen up or is that natural for a persimmon tree? It looks like it's only two to three inches thick, so I really dont think it'd support it's own weight. —EdWins

2010-09-23 10:10:16   Most of my spring vegetables are done for by now (still getting some late tomatoes and peppers) but I would like to know what I should plant now so I can get crops through winter. I have planted some snap peas. I have raised beds with about 8-12 inches of imported soil. —DagonJones

Right now we plant:
Cole crops: broccoli, cabbage, cauliflower, collards.
Onion family (onion starts arrive in November)
Root crops: beets, carrots, radishes, turnips.
Lettuce and greens, including chard, kale, spinach.
Peas: shelling, snap, and stir-fry.

2011-02-10 12:29:29   I recently moved into a house with a nice sunny garden spot... filled with bermuda grass. Is there any way for me to get rid of the grass in time for a summer garden? There is one small raised bed which I can keep pretty well weeded but I also want to utilize the ground space which is hopelessly full of bermuda. I don't think I have the time or money to build more raised beds. What can I do? Thanks! —ShannonSeil

Hi Shannon,
Bermudagrass can be dug out, but every little piece of rhizome that you leave behind will sprout again. You can smother it with black plastic, landscape fabric, and/or thick mulch, and then dig or cut it as it sprouts along the edges. Organic gardeners usually dig the bed thoroughly, adding whatever organic material they are using (manure, compost, etc.). Install whatever watering system you are using: drip irrigation tubing with emitters, soaker hoses, etc. Then cover the bed with landscape fabric, which you secure very thoroughly to the edges of the bed with anchor pins or blocks. Cut slits into the fabric to plant your seedlings, placing them close to the water source (drip emitter or soaker).
Bermudagrass cannot grow without sunlight, so it will only sprout along the edges — and possibly where you have cut in to plant your tomato plant. Keep covering any foliage that you see, or keep cutting it, so it doesn't overtake your vegetable plants. Some people spray the tops with organic herbicides derived from soap or vinegar, but those only kill back the foliage.
Systemic herbicides such as glyphosate (RoundUp) work by killing the whole root system of the bermudagrass. They are labelled for careful use around edible plants, but they are most definitely not organic. —DonShor

2011-02-15 10:42:41   So I brought my Hybiscus plants inside last fall — and some have been blooming nicely all winter. What temperatures do I look for before I put these back out in the yard? (No special place, just outside in general.) THANKS! —LoisRichter

2011-08-08 16:04:24   Has anybody here had any luck growing rhubarb in Davis? —MeggoWaffle

2011-08-08 16:27:58   What tree has been leaving a very sticky film on our patio each night? We are in a rental home in east Davis (near Slide Hill Park). Thanks! —Chamoudah

2012-03-29 08:53:38   I have some oregano in a raised bed with commercial soil in my backyard. The oregano is growing very well but it is about 2-3 years old now and it seems to have lost most of its flavor and scent. Im not sure what is going on here is this common for oregano? I don't cook with it any more because it is so bland, at this point it is just decorative foliage. —DagonJones

2012-04-17 23:02:40   April 17,2012


I am a long-time listener of your podcast. I love it. Thank you! It has given me many pleasant, peaceful hours.

I live in San Mateo, CA (near San Francisco) and this time of year there are many beautiful flowering trees (white flowers, pink flowers). I THINK they are either plums or cherries, but am not sure. Here's my question:

Any insight you have will be MUCH appreciated. (I have tried looking is several tree-identification books and online, but was unsuccessful in finding how to distinguish a flowering cherry tree from a flowering plum.)

Thanks so much!!!!!!!!!!

Nancy Pope

You will find these visible nectary glands on cherry leaves. —DonShor

2012-05-21 10:13:02   I am moving to Las Vegas at the end of the month, and I would like to keep one or two potted plants on my back patio there. What types of plants can withstand the Las Vegas climate besides cacti? —LoriOrf

The key thing really is watering and protection from heat, particularly for edible gardening. Check the local desert garden at [WWW] and find the good local independent garden center for tips on how locals manage those. —DonShor

2012-07-14 09:12:53   my tomatoes are doing horrible this year, they all have a brown spot on the bottom of the fruit and the plants look wilty. I was told that the brown spots are from over watering, but why would they be droopy? —DagonJones

2012-07-18 13:43:26   A bunch of my Roma tomatoes have flat, black areas on the bottom. Any idea what's going on or how I can fix it? It is only happening on one plant (my only Roma out of my 3 tomato plants) and doesn't seem to be affecting all of the tomatoes on that plant.... yet. We cut a ripe one open and the inside looked and tasted normal so perhaps it's just a superficial thing that we have to deal with? —JenniferCook

2012-07-18 13:45:38   Ummm, ignore me... maybe I should learn to read the rest of the page before I ask a question! —JenniferCook

2013-03-19 11:33:40   Is now a good time to plant tomatoes? Someone told me I should plant 1/3 now, 1/3 in 2 weeks, and another 1/3 in 4 weeks, what do you think of that? —DagonJones

2013-03-19 12:56:31   There's been an aphid explosion in our garden. It's really gross, there's aphids on aphids and you can barely see the plants in some cases. Should we rip everything out before we plant again? Do the aphid deterrent plants work? —MikeyCrews

** Ladybugs can be purchased at local retail [nurseries]. Release them when it is cloudy and cool, overcast, and preferably at the end of the day. —DS
bug.jpgThis guy or girl (ladybug) just massacred a dozen aphids. They're available at local retail [nurseries] fly.jpgThis guy looks like he might be eating aphids, though not fast like ladybugs? leatherwings.jpgVoracious aphid eater: leatherwing beetle

2013-04-08 17:08:27   Can I compost my expired multi-vitamins? What about expired iron pills? —MeggoWaffle

2013-07-19 13:30:34   I am planning on building some tall raised beds in my yard 8x4 and 2 feet tall. I just dont want to bend over any more to garden but I dont want to have to pay a bunch of money to fill these with 7 yards each of expensive top soil. how thick should my top soil be and what should I fill the bulk of the bed with? I was thinking just fill dirt or maybe even straw bales because they are easy to transport. —DagonJones

Fill dirt could be anything, from anywhere. If you know where it’s from, what kind of dirt it is, what the history is, then you could be fine. But otherwise, you could get problems (why are they getting rid of it?). A pool company that is installing a pool in Davis might have something suitable.
Straw bales disintegrate, obviously, and have water and nutrient management issues. Straw bale gardening is very popular right now, but I expect this trend will pass quickly as people realize they have to completely rebuild those every season. You have to water a LOT and you have to fertilizer all the time. They don’t ‘hold’ food for the plants. On the plus side, the straw bales do improve the soil as they decompose.
Topsoil is usually a sandy loam. It tends to drain very fast and have nutrient-retention issues. But with added organic material, and addition of some clay-containing native soil, you can create an ideal garden medium.
The very best is to use some of your native soil, mixing that about equal parts with a topsoil/compost blend that you purchase. That way you have a gradient of soil type from this faster-draining mix down into your native soil below.
You still need to supply nitrogen to the imported soil, and you’ll have to water it more frequently (typically twice as often) as your native soil. Nitrogen from organic sources lasts longer, but still you need to add some every season @ 2 to 3 lbs. of actual nitrogen per 100 square feet. That is, for example, 20 to 30 lbs. of a 10-1-3 fertilizer, or 60 to 90 lbs. of chicken manure (3% N) each spring and each fall.
I see lots of problems with raised beds due to the soil mixes that are used. Most common are water stress and nitrogen deficiency. The higher the bed, the more of a problem. 12 to 18 inches is better than two feet. —DonShor

2014-02-16 19:46:28   Am I going to kill my basil if I put it outside in pots right now? I think it's normally a bad idea but with the weather we've been having I have no idea. —JenniferCook

2014-03-17 11:34:46   I am building a trellis in my backyard for shade. I am planning to train some wisteria to grow up the posts to provide shade. The 4x4 posts are set into 16x16x16 inch concrete footings so the closest I can get the plant would be about 8 inches from the post. What is the best way to train wisteria? specifically should I just plant it as close as possible to the post and then guide it to curve over as it grows? How much water does it need? and where can what size plants should I start with? —DagonJones

2014-04-11 18:01:20   I just bought some blueberry plants for $1.99 at Grocery outlet. I am going to plant them in my backyard. I can either put them in the ground or in my raised bed that has good soil. The earth where I live has a lot of clay but I would rather have it in the ground so I can train it to grow up the trellis on my fence. Also what about sun? full partial or shade for blueberries? —DagonJones

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