The Garden Plot

Adrian Higgins (The Washington Post)

Got a chronic case of green thumb? Like getting your hands dirty? Adrian Higgins, garden editor for The Post's Home section, is here to help. Higgins is a firm believer in "tough plants for tough times" -- the varieties that combine good looks with stiff resistance to disease and pests. He currently rules over a garden filled with spring bulbs, daffodils, ornamental onions, perennials, asters, yarrows, hostas and day lilies. Higgins, an avid organic gardener who believes chemicals are a last resort, also tends his own herb and vegetable gardens where he grows peas, garlic onions, lettuce, rhubarbs, radishes, carrots and more.

Higgins is the author of two books, "The Secret Gardens of Georgetown: Behind the Walls of Washington's Most Historic Neighborhood" and "The Washington Post Garden Book: The Ultimate Guide to Gardening in Greater Washington and the Mid-Atlantic Region."

Editor's Note: Washingtonpost.com moderators retain editorial control over Live Online discussions and choose the most relevant questions for guests and hosts; guests and hosts can decline to answer questions.

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Alexandria, Va.: Can I plant parsley for this fall?

What can I plant this late in the year?

Adrian Higgins: parsley is perfect for planting now, either in a well drained bed or a pot that is frost proof. Both flat leafed and curled leaf parsley are quite hardy and will survive through the winter. It may flatten and become unuseable with prolonged freeze, but it will spring back in late winter and provide a crop through the spring, when it should be discarded before it bolts. But in a cozy corner this winter, facing southeast, it should indeed be ready for kitchen use right through the coldest months.

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Annandale, Va.: Dear Adrian,

I know that the "right" answer is to consult an arborist, but I remember from "To Kill A Mockingbird," Boo's father filled-in the hole in a tree with cement.

What do think as a last ditch effort to save a failing tree?

Adrian Higgins: This was a practice widely employed years ago, the theory being that it would provide some inner strength lost through rotting. But it is frowned upon today as a method that may do more harm than good in part because it doesn't address the cause of the rotting, which continues. Moreover any tree that needs a core of concrete is in bad shape and should probably be taken down.

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Frederick, Md.: I have morning glory plants in two pots on my deck. The have grown very rapidly and I'm afraid i've set the pots too close together. I have about 50 vines in one clump on my deck railing. I want to move the pots away from each other. Will the vines tollerate being unwraped and rewraped?

Adrian Higgins: Fifty? Five-Oh? Do some serious thinning now and the remaining vines will fill in, even with only six to eight weeks before frost. I would only leave at most five vines in one pot, and better three. Next year, remove the seedlings as they emerge.

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Cleveland, Ohio: I planted pumpkins (Lack o' Lantern type) for the first time this year and they have been flowering prolifically for some time, but have still not set any fruit.

Will I still get any pumpkins at this late date? Some parts of the vines look a little shriveled up, but for the most part they seem to be thriving.

Thanks!

Adrian Higgins: Most of the blooms are males, the females do tend to come later and it may be that your are just setting fruit. It is late, though, especially in your zone 5? climate. You may have a lack of pollinators. Look for bumble and honeybees on the blossoms. The vines that have shriveled may be victims of the squash vine borer and they will not set any fruit with any chance of ripening, in my experience.

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Burke, Va.: Please help a complete novice. This is my first house. My back yard developed a couple of bald spots (about a foot in diameter) as a result of spilled paint. The grass is definitely dead there and I finally realized that it is not going to "grow in". What steps do I take to correct this problem?
Thanks!

Adrian Higgins: Buy a bag or two of compost or peat moss, use a garden fork to dig in into the soil of the dead areas. Rake it smooth, and sow with fresh turf type tall fescue seed, but not so thickly that you can't see space between the seeds. Keep it lightly misted twice a day until it germinates, and keep it moist thereafter until it is time to put the hose away this winter. Cut with a sharp blade once the grass reaches three to four inches tall, and cut on the mower's highest setting. You may want to spread a little straw on the spots to keep the birds off and the soil moist.

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Washington, D.C.: Adrian:

I have an atypical question: what did I do right? This year for the very first time my container-grown species rosa rugosa (red and white) have developed gorgeous plump red hips. I can't recall doing anything different with fertilization or watering. Has this been an unusually favorable season for hip development?

Adrian Higgins: I don't know except that if you go farther north, you will find far more hip set on rugosas than down here. I wonder if the cooler summer has induced a better fruiting.

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Great Falls, Va.: I am new to this area and have a question regarding River Birch. I seem to have gypsy moth webs on some lower branches. How is it best to handle these?
Thanks

Adrian Higgins: There are a lot of fall webworms about this year, more so than other years. Cut out the ones you can reach before they hatch and chew everything. If the worms are young you can kill them also with a spray of Bt.

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Arlington, Va.: Hello, Adrian:

Thanks so much for your chats. I clipped the article on water gardens -- I'm looking forward to creating one "someday."

Can you tell me if lacebug infestations on pyracantha and serviceberry would be fatal? What should I spray with? Also, I have these orange and black spotted/striped beetles all over my horseradish (nearly dead) and cleome plants? Any ideas? Or should I try to horticulture extension people?

THANKS! I'm surprised that it's been such a bad year for bugs. For once, the spider mites aren't bad, but lots of other things have taken their place.

Adrian Higgins: Spider mites flourish in hot, dry years, hence the lower numbers. Lacebugs will if unchecked weaken and stunt their host plants seriously. They can be controlled by spraying the underside of leaf surfaces with a light horticultural oil in April or May before populations multiply.

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Richmond, Va.: Two questions from a novice indoor gardener:

1. I bought a lime tree and a sticky, crystalline substance has developed on a few leaves. I picked those off, but should I be worried?

2. I think gnats are developing in my pots, since they scurry when I water my plants. What can I do?

Thanks!

Adrian Higgins: Hope you are drying out in Richmond and that Frances misses you and gives my garden a nice but not ferocious soaking. The citrus is showing signs of honeydew, with are the secretions of pests such as aphids or mealy bugs. Yes, you need to attend to it, especially before bringing pots indoors. Look for small brown or white bumps on stems or leaves, these are mealybugs, which are best killed by daubing a cotton swab in rubbing alcohol and rubbing on the insect. Aphids can be killed with insecticidal soap.

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Zone 6: Hi Adrian,

I'd like to have a hummingbird garden next spring, and would like some suggestions of perennials that I could try to get established before the weather gets cold. Any thoughts?

Adrian Higgins: If you can provide excellent drainage, I would go with agastache and penstemon and then fill out the bed with various sages.

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Hyattsville, Md.: I have a 2-year old peony in a too-shady spot. I know peonies don't like to be moved, but since it is unavoidable, is it better to do this now or next spring?

Unrelated question: my lilies were attacked by some sort of aphid-like insect (larger and dark colored). Any ideas on what they are and how to treat? Insectical soap didn't seem to help, but I probably needed to apply it more often.

Thanks!

Adrian Higgins: September is a great month to move peonies, just make sure that the new bed is sunny and that you place the eye buds of the crown between an inch or two inches, no more, below the soil surface. They may sulk next year but should bloom again the following.

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Arlington, Va.: I have some large Japanese Hollies as hedges and three have died completely. It looks like one of the others has spider mites. Could this be what killed the other three? And how much insecticide do I need to spray on the hollies? Saturate it? Of just a light spray? The garden center I went to just told me to use a small hand squirt bottle. Will this work on large hollies? And will it harm any of the other hollies that don't have spider mites to spray them with it?

Adrian Higgins: Many insecticides don't kill mites, which are arachnids. Instead the insecticides kill their predators, so the mite problem becomes a mite worse. YOu can spray them with horticultural oil, which smothers them. Mite treatment is much more effective early in the season than now, after the damage has been done. I would put the spray in a two gallon pump sprayer.

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Springfield, Va.: I have some chives, parsley, mint, basil and rosemary plants in my garden. From last year, I knew some of them didn't do so well in the winter and I had to buy new plants in the spring. I was planning on potting them because I dont' want to lose them. Which ones should I definitely! pot and what is the best way to do that (one big pot or lots of little pots). I tried to put the herbs in pots before and they didn't seem to do very well so I just put them in the ground. Thanks for any advice you can give.

Adrian Higgins: All things being equal, these herbs do better in garden beds of properly prepared soil than in pots. They can live quite happily in pots if you keep them watered and occasionally fed, but they will need less fussing in a sunny bed that is well drained. Basil will die with the frost, mint will spread in a bed, chives will be quite hardy and the rosemary needs a sheltered spot, either in a pot or in the ground.

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Springfield, Va.: Hi Adrian,

You always recommend adding organic material to help keep a lawn healthy. How exactly would I do this? Should I buy several bags of compost and just rake it into my existing lawn? Do they have spreaders available that might work better?

Adrian Higgins: I would use a core aerating machine and then backfill the plug holes with compost, either by the bag or in a bulk delivery. It also helps to give a light dressing of compost to the lawn surface, especially if you are overseeding this fall.

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Washington, D.C.: Adrian,

How long does it usually take a tomato to fully form from a blossom? With early October as a frost date in this area, at what point does it make sense to pull out the blossoms so that the already fruited plants will develop? Thanks.

Adrian Higgins: It is still possible for green fruit to grow and ripen. In about four weeks, it become a hopeless cause because the cooler air temperatures retard the ripening rate.

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Arlington, Va.: I transplanted two azaleas last spring. One is doing great, the other one looks like it is dying. Would cutting it back be a good idea?

Adrian Higgins: I wouldn't cut it back without understanding why it is dying. Is it in too dry a site, too wet? I would dig it up and see if you can detect a problem with the roots and the soil in is in, and then replant it in a more favorable site. Azaleas prefer rich, well drained soil that is on the acidic side.

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Maryland: Good afternoon Adrian -- Thanks so much for your good advice in the past. Hoping you can help me out again.

A large maple tree in my backyard recently had to be removed due to storm damage. The tree afforded a great deal of privacy and the yard looks bare and too open without it. I'd like to replace it with some other trees that would provide privacy but would not grow quite so large -- not so large as to require a lot of expensive maintenance or be dangerous in the event of further storm damage. I've gotten recommendations for Leyland cypress. What would you recommend? Thanks.

Adrian Higgins: Do not plant a Leyland cypress. I would consider a rahter compact and nice Southern magnolia cultivar such as Edith Bogue. There is another variety whose name I've forgotten but will come to me soon.

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Olney, Md.: Howdy Adrian.

I have a question about fertilizing tree hibiscus. I bought two in the spring and named them May and June. They get plenty of sun during the day, and I keep them watered.

June is the bigger one, and is just showing a few buds. May has been blooming since late July. However I am concerned about the leaves. They are lime green instead of deep green.
Are my hibiscus just in their normal early stages of growth or should I be feeding them? Any tips would be greatly appreciated.

Adrian Higgins: A good organic feed will give them the nutrients they need. Don't overwater and give them good drainage. If you try to green it up now with nitrogen fertilizer you will promote new growth at a time when the plant needs to be thinking about rest.

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Arlington, Va.: Adrian,

Earlier this year, you recommended lawn aeration, a layer of compost, and overseeding and said March would be the right time.

Is this also a good time?

Do I put seed in the aeration holes, or just rake it into the compost/compro layer?

Thanks.

Adrian Higgins: March is the second best time, now is the better time. You can also allow seed to fall into the holes and backfill them and they will sprout.

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Ft. Washington, Md.: Hi Mr. Higgins:

Can you recommend a Web site or book that shows pictures of plants/flowers so that I can figure out what plants and flowers are in my yard? I am in a new house with a very nicely planted front yard, I don't know much about flowers but I would like to identify them so that I know the proper way to care for them.

Thanks for your assistance.

Adrian Higgins: The best way to get a sense of what plants grow here, and how they grow here, is to go to a botanic garden such as Brookside Gardens or the National Aboretum with a camera and a pen and pad and record what takes your fancy.

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Annandale, Va.: I have three tree seedlings, two maple and one beech, that I transplanted from where they sprouted (but weren't wanted) into pots. What should I do with them this winter if I'd like to transplant them somewhere outdoors in the spring, pmant them or bring them inside?

Adrian Higgins: Do not bring them inside. They are hardy plants that need winter dormancy.
If you don't know where they are yet to go. Prepare a protected bed for them and sink the pots into the soil to protect their roots from freezing. They can be planted in their permanent homes in the spring, though now would be a better time for that.

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Gainesville, Va.: Submitting early due to a meeting. Recently moved into a townhouse that faces due West. I'm a novice gardener but would like to add color and texture to our front yard, which recieves direct sun for the majority of the afternoon. I would appreciate any suggestion you may have.

Adrian Higgins: Build garden structure with trees and shrubs, and then fill in with herbaceous stuff like perennials and groundcovers. They key is to use material that will stay in scale with your site. Don't put a tulip tree in a tiny townhouse yard, better a Japanese maple or a redbud, for instance. You are fortunate in having a sunny location, but realize that as your trees and shrubs grow, they will cast shade on the plantings beneath them, so be prepared to change those in time.

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Arlington, Va.: Okay, so I have flower beds I mulch well. I even put down Preen to prevent weed growth. But the empty portions of my bed continue to fill up with weeds.

Now, look at any professionally landscaped flower bed outside an office building. No weeds. And they only come to maintain them a couple of times a season.

What is the secret here that professional landscapers are not sharing with us re: weed control?

Adrian Higgins: After preparing your soil, you can lay rolls of landscape fabric, and then plant through them. The fabric then is covered with a couple of inches of mulch. This may be the practice you see in commercial beds where the weeds are kept at bay. Even then, weed will grow in the mulch. Two weedings a year is optimistic, to say the least.

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Fairfax, Va.: Hi Adrian --

Your online column has been so helpful. This time the question concerns my 600-square-foot vegetable garden. What procedures (and in what order) would you perform this late fall to get the area all ready to go in early spring for planting (i. e. soil friable, weeds contained) and what soil amendments etc. would you also add at that time? Thanks.

Adrian Higgins: I would always try and stay on top of the weeds. Yours is pretty big, I think I would do three things: Grow winter hardy crops in some beds, such as garlic, kale, chard, spinach and leeks. IN other areas I would sow winter rye or hairy vetch to keep the weeds back and provide a green manure to turn in next spring. Third I would leave some soil open and add organic matter in the fall that is allowed to break down over the winter. Turn it in, with winter weeds, before planting in 2005.

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Reston, Va.: Mr. Higgins --

When do I apply mikly spore for grubs?

Thanks.

Adrian Higgins: I am skeptical of that stuff having much effect, not only from my own experience but in talking to other gardeners. If you have faith in it, follow the label instructions.

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Arlington, Va.: I know that it is about time for fall lawn renovation and am wondering what steps will be enough to get my lawn in good shape for the winter. I have addressed my drainage problems this year but the lawn just hasn't grown back in quite right even after several months. One of my top concerns is that because I have dogs who do enjoy the yard I am hesitant to use weedkiller or to completely strip the yard for any extended period. But I'd like to do whatever I can so that this winter the yard will not to turn into a messy muddy patch. Thanks for all your great advice.

Adrian Higgins: Now is the optimum time for lawn renovation. If you can't get it to grow with adequate soil preparation, good seed, proper watering, and straw to retain moisture and control erosion, you never will. Try and keep the dogs off until the turf is established.

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Derwood, Md.: Can impatiens self-seed? I have two barrels of the stuff next to my front walkway, contained and about two feet above ground level. I now have impatiens all over the brick path, up to 8 feet away, in places where I have never had impatiens. Is this squirrel mischief?

It looks gorgeous, so I'm enjoying the spontaneous beauty, but I was curious.

Adrian Higgins: Impatiens will self seed. However, the seedlings often don't resemble their hybrid parents, and may be leggy and tall.

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Washington, D.C.: Hello! Thanks for your chats.

I got a wonderful moth orchid last year for a housewarming gift. It bloomed beautifully and was a pleasure. After all of the blooms died I cut the stalk at the fourth notch as instructed by my the florist who sold the plant. My orchid did not go dormant (due to the uncontrollable heat in my apartment) and began putting forth multiple new shoots/stalks. There are approximately six shoots of various sizes and directions but none are flowering. Should I cut these off? Does it need repotting? The leaves are doing well and it's definitely still growing. I'm fertilizing, too.

Thanks for your help! I know orchids are touchy plants.

Adrian Higgins: IF they are top shoots, keep them, for they will flower. You may be seeing the aerial roots form. Either way, the plant is happy and keep it misted. Alas, we have run out of time once more. Same corner of the cyberworld next week.

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