The Garden Plot

Adrian Higgins
Washington Post Garden Editor
Thursday, March 19, 2009; 12:00 PM

It's been a cold winter, and many green thumbs have been impatiently waiting for spring to arrive. Washington Post gardening editor Adrian Higgins was online Thursday, March 19 to offer advice on getting lawns, flower beds, vegetable patches and window boxes ready for the warm days ahead.

A transcript follows.

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."


Bethesda, MD: I'm so happy you are here today. It must mean spring is about to happen to us. Are you going to be able to chat on a regular basis this year?

Do you have any experience in repelling deer? We have a group of 3 youngsters who are coming through on a regular basis this spring. They are not as skittish as the adults, so it's proving difficult to discourage them. After last year when the deer ate EVERY SINGLE daylily bud just before they started to open, I am feeling some desperation to get the situation under control. Because of the layout of the yard I don't think it's going to be possible to enclose it with fencing. Is it hopeless? Do I need to replace everything with boxwood (ugh), euphorbia, and ferns? They just ate most of a couple of nandinas.

Adrian Higgins: Hi, everyone, great to be back, if not on a regular basis. I have not had deer, I have suffered other pests, but not deer. I have talked to a lot of gardeners and experts who have. The key is to exclude them before they start browsing in your garden, and this can be done effectively with black netting stapled to posts or even trees. Repellents can help too. A product called Deer Stopper doesn't have the foul smell of some concoctions and may work. Blood meal, a natural fertilizer, will also keep them at bay for a while, perhaps during key moments such as daylily bud development.


Silver Spring MD: Hi, I enjoyed your article today, though I must admit I'm a complete newbie. What did you mean by transforming a concrete front walk with "framing it in brick, cobbles (what the heck are cobbles?), or clean cut bluestone"? Does that mean lining the sides of the walk with these materials? Where might I get these materials? Are there any websites that would give good examples of easy DIY projects along these lines? Also, where might I get large and attractive pots for the front steps that are not too expensive?

Thank you!

Adrian Higgins: It means that you edge the concrete path with these materials, rather than lay the masonry over the concrete path. Cobbles can be large river stones or square hewn granite blocks.


Bowie, MD: I planted some Elephant Ear bulbs two weeks ago when the weather was 70 degrees. As I was planting it the instructions said to plant the pointed end up. My problem was that it wasn't always clear to me which end was the pointed one. My question - is there another way to determine which end to plant downward?

Adrian Higgins: I would be a little leery of planting dormant bulbs in cold soil. I think I would have waited a month. But you may get away with it. Look for a ring on one side, this is the point at which the roots will emerge. If still in doubt, you can plant the bulb on its side, and the plant will figure it out.


Fredericksburg, VA: Is there a cost-effective way to aerate the lawn? Can't afford to hire someone, and renting the machine is expensive and heavy.


Adrian Higgins: I agree the machine is a monster and I think it cost me $100 or so the last time I did it. One option is to go in with a neighbor or two, and split the cost. Another is to top dress the turf with a thin layer of aged compost. This is a long term approach and needs to be done once or twice a year. The microbes in the soil will eventually incorporate the matter into the soil and open it up some more.


Bulbs: In the fall I planted some daffodil and tulip bulbs in my front yard (lots and lots of afternoon sun). Both are budding at the same time; did I plant the tulips too shallow or is it okay? I thought he daffodils would come before the tulips.

Also, are there other bulbs (or small perennials) that I can plant with them that will flower later in the season? There are lots of tree roots in the small area, so I like bulbs because I can easily find spots for them among the roots instead of having to find bigger areas for larger plants. Are wildflower seeds an option for the area?

Adrian Higgins: Daffodils generally bloom before tulips, but there are early, mid and late season varieties of each. Later bulbs? Camassias, Spanish squill, alliums.


Catonsville, MD: Our yard has seen years of neglect, and vines and weeds have overtaken a huge swath of forsythia and other shrubs. I'm not sure what is there or how to go about reclaiming it? What is a good strategy to consider?

Adrian Higgins: As I mentioned in the package today, I would consider simply chopping your forsythia to the ground, and remove the vines while you're at it. You will need to treat the cut vine with some herbicide to stop it from regrowing. Watch out for poison ivy.


Silver Spring: Hi Adrian!

What's the process for reseeding my lawn? I have various patchy spots of dirt in an otherwise decent lawn. Obviously, I'd like a dark green, lushy lawn, but I'll settle for one that isn't patchy. If it helps to know, I haven't yet done anything with it (no aerating, etc.). Thanks!

Adrian Higgins: Hi. September is the best time for seeding but now is the second best time. You can overseed the lawn now, i.e. just thicken it with fresh seed without replacing it. Bare spots should be cultivated and seeded. Be aware that most preemergent herbicides will prevent grass seed from sprouting.


Silver Spring, MD: We have a number of hostas that we want to move from our front yard to our back yard. (We are having our front yard redone.) They are just starting to peak up out of the ground. When is the best time to transplant these? How do we best prepare the soil in the new location?

Thanks, as always, for the helpful advice.

Adrian Higgins: DO it this weekend before they put on any more growth. They may need dividing at the same time. Hostas thrive in partial shade and with rich, evenly moist soil so the more soil enrichment you can do, the better.


Silver Spring, Md.: Is it possible to move bulbs, now throwing up shoots, if one is careful to dig around the bulb and carry plenty of the surrounding soil with it? I'm planning to install some stepping stones in a garden, but wonder whether I should wait until later in the spring or early summer when the tops of my bulbs have dried off.

Adrian Higgins: If you were really careful, yes, and that means not ripping the bulb roots that are now fully expressed. Plant them at least at the same depth they were growing.


Alexandria, VA: Extreme pruning question: You wrote about cutting back azaleas severely, but what about other shrubs - for example, holly bushes? Can that be done safely?

Adrian Higgins: Hollies will take hard pruning yes. And they can be clipped into a hedge. You see Yaupon hollies treated this way in Colonial Williamsburg. Don't slice through a leaf, remove it.


Reston, VA: Hi Adrian,

I have two questions I was hoping you could help me with:

1. We have some fairly large rhododendron plants in our yard. The leaves are drooping considerably on them, and they are a yellowish-green on one of them. Is that normal? Will they straighten out/green-up when warmer weather hits, or is this a sign of a problem?

2. Can you recommend a good book that would help complete novices identify the plants in their yard?

Adrian Higgins: Your rhododendon may be suffering from winter leaf burn, or from a condition called chlorosis caused by the soil becoming too alkaline. You should apply acidifying nutrients formulated for rhododendron, and water them in. Reader's Digest has just reissued its Illustrated Guide to Gardening, and this would be a good all round book for beginners.


Victory gardens!: I'd like to urge everyone who possibly can, to raise a vegetable garden this year. If you don't have a patch of land (or it's unsuitable), then perhaps offer to lend a hand to an elderly neighbor who's no longer able to manage a garden alone (in return for part of the harvest). Or sign up for a plot at a community garden (will the "Post" be running a list of sign-up info?).

Instead of giving a needy friend some basic vegetable seeds (because no one enjoys feeling like a charity case), I bought her a dozen packets of tastier, more unusual varieties I particularly like but with which I knew she was unfamiliar -- rainbow Swiss chard, red leaf lettuce, mixed colors of sweet peppers, purple string beans, yard-long beans, golden zucchini, white corn, spaghetti squash, etc. -- so she could feel comfortable accepting them as a gift without losing face. In turn, she has chosen to share part of each packet with another friend who also gardens, so has also gotten the opportunity to be a giver and "spread the wealth."

Adrian Higgins: I agree entirely, and much of my work in recent months has been to this end.


No. Virginia: My in-laws have a gazillion lilies of the valley and every year when they bloom, I say I'm going to move some to our yard, on the shady side. This year, I mean it! :) When is the best time to dig and transplant them? I figured when they are just showing new growth . . . Tips are appreciated.

Adrian Higgins: I suppose you could try now. The best time would be when the pips go dormant in late summer.


Alexandria, Va: Greetings! I really liked the video of your garden.

We recently moved--our backyard consists mostly of 50-plus year old oaks. The previous owner primarily planted azaleas around the grounds, but we tend more toward perennials. We can envision losing some of the azaleas, but wouldn't want to cut down any mature trees. Of course, that leaves us with shade virtually everywhere--any suggestions?


Adrian Higgins: You can do lots in shade, albeit not deep dark shade. You just have to place more emphasis on foliage ornament than flowers. But that's not a bad thing. I would get Timber Press's Pocket Guide to Shade Perennials.


Alexandria, VA: Hi! I'm one of the impatient green thumbs, and I've been working since early February getting several raised beds ready in my backyard for a vegetable garden this year. I'm really interested in succession planting and intercropping (planting corn near squash, etc.) and wondering if you have any thoughts or tips? Thanks!

Adrian Higgins: I would think like a gourmet cook rather than a farmer, i.e. don't grow huge swaths of things that will yield too much all at once. Think of the season in three acts, Now to Memorial Day (salad greens, radishes, carrots, beets, peas) Memorial Day to Labor Day (cukes, squash, tomatoes, peppers etc.) Fall (greens, Asian greens, brassicas, winter squash, the last planted in June). Plant beans in succession through the season and grow them on poles to increase your real estate.


Rockville, MD: I planted sweet pea seeds a couple weeks ago because the packet said "plant as soon as soil can be worked". Then we had that freakish snow storm. The peas haven't come up yet. Are they probably dead?

Adrian Higgins: Probably not. Sweet pea seeds tolerate cold soil. This plant doesn't perform too well here, resenting the heat as it tries to bloom. Some gardeners sow in November, others in January to allow good root development before the spring.


Re "Watch out for poison ivy": Let me second this -- especially while the stuff is still dormant, so cannot be recognized by its signature three leaves (with the middle one on an inch-long stem). As you've probably suspected, I speak from experience, as I wound up with such a severe rash on my face, including one eye swollen shut, that I had to go to the doctor, who prescribed not only a topical cream but also prednisone and benadryl pills. Wearing work gloves didn't protect me from getting the allergen on my clothes, and it's hard not to come into contact with them. Also, do not touch your face while wearing your gloves, in case any poison ivy juice has gotten on them.

I now can recognize dormant poison ivy: the vines are slightly fuzzy, and rusty in color.

Adrian Higgins: Thanks for that.


Rosemary hedge?: Adrian,

We saw a lovely rosemary hedge a couple of years ago in East Anglia. Is it possible to do that here? Are there any rosemary cultivars that would work better in Washington? Thanks!

Adrian Higgins: I think shearing rosemary here would send it into dire stress. I would grow it as a natural hedge, that may be shaped but not clipped. The problem is, the hardiest varieties are also the ugliest, so I would want to do it with some of the more marginal varieties. And if one were to die out, it would be like looking at a smile with a tooth missing. But worth a go.


Chicago, IL: We have been through several rosemary plants this year. We keep them about 10-12 feet from a south facing window and water them semi-regularly, but every plant has dried up then died, some of them within days of buying. We've bought them from a local nursery, a farmer's market and Whole Foods and had the same issue with all of them. Any idea what we are doing wrong?

Adrian Higgins: Rosemary is not a house plant. It will grow in a cool conservatory or greenhouse, but not with the dry heat and relative darkness of a home.


Pittsburgh: Hello Adrian, last year we were compelled to take down a large maple tree that had split and outgrown a very small circular bed bordered by our concrete driveway. We would like to plant a small ornamental that doesn't drop a lot of debris. Our arborist has recommended a katsura-- how does that sound to you?

Adrian Higgins: Katsura would work. Or perhaps a redbud.


Tomato ladders: I was thinking of ordering some tomato ladders to support our indeterminate vines, and really try this year to train them with one leader and no side shoots, to maximize production in our small space. I'm just curious if you've used the ladders or if they are just a gimmick; should we stick with stakes or cages? Thank you.

Adrian Higgins: I've seen about a dozen or more different ways to support tomato vines, I think it's a matter of choice. The wire cages that are sold are entirely too small. The best system I saw was a large cage with a five foot wooden stake on each side.


Ballston, Virginia: I am looking for direct-sow, fail-safe flower seeds for my young daughters to plant this year.

This should be a no-brainer but in the past I've had NO success with cosmos and alyssum, which should be super-easy, and don't want them to be disappointed.

Can they grow sweet peas?

Adrian Higgins: No. I would try nasturtium, but soak them overnight in hot water.


East Falls Church: I have never grown swiss chard or broccoli (would like to try broccoli raab) and wonder when I should plant seeds. or do they sell the plants?

Also, we have a lot of part-sun areas - the full sun will be reserved for tomatoes and eggplants, but what can I put in the less sunny spots? Thank you.

Adrian Higgins: You can sow chard now. I would wait until August to sow your broccoli and broccoli raab, and have them as a fall crop.


Alexandria: Welcome back professor, I've missed your chats! I'm planning to install a veggie garden in my yard. How should I prepare the land for the garden? I've heard different approaches, including using landscape fabric, newspaper, and other materials. Is this necessary? Please advise!

Adrian Higgins: Thank you. Alas this is just a special appearance linked to our spring gardening issue of the Home section. The key is to create raised beds, separated from paths, and richly amended to allow good root development and moisture retention. I tell people to take six or eight inch wide boards and peg them on their sides and backfill with soil and aged compost. Ideally, the ground beneath has already been dug and amended. This is a great winter project, by the way. (assuming the ground isn't frozen).


Washington, DC: Last year a blight stunted my tomatoes and significantly decreased their yield. Do I have to worry about my tomato plants this year and if so, what measures can I take in order to avoid diseased plant and to promote healthy ones?

Adrian Higgins: Yes you do have to worry about blight returning. Ideally, you should put your tomatoes in another bed. If you really want to beat the blight, you need to put down landscape fabric, mulch heavily with straw, and remove about the lower 12 inches of foliage (healthy green leaves as well as those beginning to show blight)in early summer.


Harrisburg, PA: I've been thinking of mulching a small area with stones--an area that gets a lot of eavespout drainage that washes bark mulch out onto the sidewalk. Do I need to lay black plastic under stones I put down?

Adrian Higgins: No, unless you want the water to be sheeted away. Just make sure the stone mulch layer is thick enough to stay put. A three inch layer of pea gravel would work.


Springfield, VA: I planted some bachelor's button flower seeds in a seed starter box. They sprouted in 4 days instead of 10, as stated on the seed envelope. I'm misting them every day with warm water so they have enough water. However, many of them fall over and won't stay up. Am I doing something wrong or is this normal?

Adrian Higgins: For seed starting, you need to have lights close to the seedlings to prevent them from stretching. No more than 12 inches from the seedlings, and raise them as the plants grow. Seedlings are naturally lank but they shouldn't sprawl like a vine. I find having a fan on low helps to keep them more upright.


No. Va.: For the chatters, we built a raised bed a couple years ago and if you are thinking of doing it, it's really very easy. They sell corner connectors at a hardware store, I guess for decks, so you just put the boards together. It did require a LOT of soil to fill. But we had great productivity in the space. I would highly recommend it for those warm spring days when it's still to early to actually plant.

Adrian Higgins: Thanks for that.


Mulch: You mentioned mulching with straw but where on earth do you buy straw in an urban setting? They do not sell it at Home Depot. Sorry if this is an ignorant question.

Adrian Higgins: You can get it at independent garden centers, or Southern States, I think. Avoid hay, which is weedy.


Lilies: Hello, when should I move oriental lilies? They are in too much shade and last year barely bloomed.

Also, how should I prune my hybrid clematis, planted last year. It is already growing, much to my surprise.

Adrian Higgins: Move the lilies now, but mind the roots. Plant them deeply in really rich soil. The clematis can be pruned about 18 inches above ground to just above a pair of swelling buds.


Butterfly weed problem: I've bought at least six asclepias plants and lost them all. They're labeled full sun so I put them in my south-facing garden, where they died (I'm in Ellicott City and have clay soil that I"m constantly amending). I read that they like wet feet so I put new ones on the edge of a rain garden we just had installed. They did not show any signs of growth, although they were still green, by last summer's end. What am I doing wrong?!?

Adrian Higgins: Get some seed and start indoors now, and put out the seedlings in eight weeks.


Silver Spring, MD: What is the best timing for putting down pre-emergent weed killer, and are some varieties better than others? Every year we struggle to time it right so that we also can overseed, which has to wait several weeks after the pre-emergent goes down. Last year we were overrun with weeds!

Thank you.

Adrian Higgins: Crab grass begins to germinate in a couple of weeks, so you can put it down in the next week or two. This only stops seeds from germinating, it won't prevent your dandelion or henbit weeds, now growing, from flowering and seeding.


Upper Marlboro, Md.: Hello, What are you thoughts on hiring a landscape architect - pros and cons? Should the company/person hold a certification in horticulture, if any at all?

Our lawn is heavily loaded with rocks and bad soil. We planted two trees to replace dead ones two years ago and they are not growing well in addition to planting some shubbery that dies. We do not have sprinkler system in place; however, we do water frequently and "feed" them with fertilizer.

Any suggestions you have would be great.

Adrian Higgins: The point I tried to make (I hope it was clear) in today's article is that you can and should hire a designer for an hour or so so that you can see your garden through their eyes. This doesn't buy anything but their time and thoughts, but you will find it valuable. The key is to find someone who is good and who is not using the consultation to try to sell you an expensive design/plant package. There is no such thing as free design.


Arlington, VA: Aaahhhh! You're like a drink of water for us thirsty gardeners! Even if brief it is refreshing. The person who wrote about tomatoes, gave me an idea. Is it feasible to "espalier" a tomato plant to a trellis? This would give me a lot more garden real estate. Thanks!

Adrian Higgins: I have seen cherry tomatoes, naturally very vining, woven between the pales of a picket fence. Very effective, but you have stay on top of it.


Central NJ: Can I use freshly chipped wood (from trees downed in a storm) as a mulch, or is it necessary to let it age for awhile?

Adrian Higgins: Fresh wood chips will actually deplete the soil of nitrogen as they decay. They are useful for woodland paths, but I would consider composting them before using them, or add nitrogen fertilizer if you are going to mulch with them.


Arlington, VA: Hi Adrian, the video is wonderful; the perennials are lovely. Do those ornamental grasses require full sun? What else do they need? Can you recommend any natives? We have very limited space but I might be willing to eliminate something else for those gorgeous grasses - lawn maybe.

Adrian Higgins: Most grasses don't grow so well in shade. Hakone grass thrives in partial shade, but is Asian. Carex or sedge, include native varieties, will take shade.


Alexandria, VA: Is our region too warm for blueberries? I've had luck with raspberries and strawberries.

Adrian Higgins: No not yet, and there are southern varieties. Check out Edible Landscaping on the Web. I think we have to end it now, please join me in thanking our producer Elizabeth Terry, who has done sterling work for all my chats over the years. I hope to be here again sometime. Get gardening you churls!


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