| The Garden Plot
Hosted by Adrian Higgins
Washington Post Garden Editor
Thursday, May 22, 2003; 11 a.m. ET 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." The transcript follows 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.
Washington, D.C.: Hello Adrian! I recently had a large concrete patio removed from my backyard and would like to replace it with sod. I wonder if the soil that spent years under the concrete needs to be enhanced in any way before laying sod. Should I have some topsoil brought in? Any advice is appreciated. Thanks! Adrian Higgins: The soil will be most compressed and this will definitely impede the ability of the grass to grow nicely, particularly in the summer. I would bring in topsoil and possibly rent a rototiller to work it in to the subsoil, to break that up. However, you have to be very careful with bulk topsoil, it is blackened and fluffed up by adding a bit of mulch and putting in large screening machines. At the first rainfall, you may have your concrete patio back. Ask the soil company to custom mix a batch for you that will be something like half topsoil, half LeafGRO or some other organic product. I would not seed it until September, however, though you could lay sod now.
Alexandria, Va.: Last week I asked a serious question about how all this rain is affecting our plants and what, if anything, we should do. You gave a flip answer about how spring always is rainy and that is lovely. Well, after another week with hard rain five out of seven days and a forecast for five more in a row like that, can I get a serious answer now, please? My plans are mildewing, slugs are everywhere, and we are still getting up to an inch per day in this area. Thanks. washingtonpost.com: Plants for a Rainy Spring, (Post, May 22) Adrian Higgins: What do you want me to do about it? If the soil is poorly drained and unworkable, don't work it. If it is puddling, build some drains, if the plants are too big, cut them back or pull them out. If they have leaf disease, remove the diseased leaves, spray if you wish, and if that doesn't do the job, yank it out and put in a plant that doesn't get mildew. All it takes is observation and hard work.
Dupont Digging: Adrian --
How does one harvest lettuce? Do you cut the outside leaves off? Shear the whole thing? Cut from the inside? How often can you harvest? Thanks! Adrian Higgins: If you are thinning and they are of useable size, take scissors and remove the leaves that way, without disturbing the roots of the neighbors. You want to keep doing this until the remaining lettuce plants are four to six inches apart.
Arlington, Va.: Adrian: I'm fascinated by the wild roses growing in the shady woods and parklands off the bike paths of Northern Virginia. The foliage is a bit lacy and quite attractive; the white bloom is an inch wide with a yellow center. They appear to be a rampant, almost invasive, grower, and I'd like to find some for a controlled area in my yard. Any idea what they're called, and who might offer them for sale? Thanks much. Adrian Higgins: This might be the multiflora rose, a highly invasive exotic that you don't want in your garden. As for roses with lovely, single blooms, try the greenbriar rose, which has the added virtue of smelling like apples.
Arlington and Herbs: Help! I want desperately to grow my own herbs (apartment balcony) but am failing miserably. Can't even get them to sprout. Disaster. What do those little seeds need for a good start? Adrian Higgins: They need even moisture, not waterlogging, sun, and time. You might be better off planting seedlings, I would.
Woodbridge, Va.: Ready by next Spring! What can I plant now that will flower and bloom during the months of June and July next summer? What bushes can I plant that will grow/spread quickly and give some color -- again, by June and July of next summer? Thank you! Adrian Higgins: Many lovely perennials flower in June and July, including rudabeckias, echinacea, coreopsis, agastache, dianthus, and the Joe Pye weed. I would go to the butterfly garden at the Smithsonian (at 9th and constitution) with a notebook and take note of all the plants you find in bloom at that point, and then buy and plant them in August or September.
Boston, Mass.: What would cause a rose (planted last year) to break dormancy this year and then die back very quickly? Ten days ago, I mounded chicken compost around it and have watered frequently, but I'm afraid it's a goner. Should I yank it and replant? What happened here? Adrian Higgins: Either the tender growth was killed by a late frost or the poultry compost was too fresh and strong, especially in nitrogen, I suspect. Wait to see if it comes back, but any sprouts from below the crown of the plant will be from the rootstock and not worth growing.
Annandale, Va.: A garden center adviser has recommended Japanese acuba for a fairly shady area of my yard. I've not heard much about this plant as being a good shady garden choice. What is the background on this plant and its use in shady conditions? Adrian Higgins: Yes, it is one of the broadleaf evergreens that do well in deep shade. There are variegated versions that really brighten a dark spot. They do benefit, though, from soil that will drain and placement in a spot that gets some air circulation to avoid fungal diseases at the base.
Downtown Washington, D.C.: Adrian, I think Alexandria would like you to make the rain stop. Please do so immediately! Adrian Higgins: The ark is almost complete.
Reston Va.: I've been told my dwarf English boxwoods have wooly aphids. Some, not all, of the leaves are curling into little balls. Any ideas for how to deal with this? Thanks! Adrian Higgins: it's not aphids, it's a pest called psyllid and you need to spray while the creature is on the wing. Let me look this up and get back to you later in the chat.
Woodbridge, Va.: We bought a small azalea plant several weeks ago. It was about 12 inches tall, with about 4-6 branches from the stem. My lovely husband accidentally stepped on the plant on Tuesday and snapped two branches off. Each branch is now in a glass of water with a few drops of fertilizer. Can they be saved? The bush doesn't look too bad -- just sparse. Any advice? Adrian Higgins: The cuttings may well root, but I would transfer them to a tray full of moist sand, and put a plastic bag over them. By the fall, they should be ready to set out. Make sure that the torn branches are cut cleanly on the shrub. In time young shoots from other branches will fill in the gaps. Careful pruning to direct side branches will aid this restoration.
Maryland: Problem with my butterfly bush. It's leaning heavily this to one side, most likely to get more sun. Should I stake it to get it more upright? I'm worried it will fall over. Love these chats -- I always learn something. Adrian Higgins: They really love lots of sun. I would cut it back quite hard and give it an opportunity to try again once the sun comes out. If it is still too shady, consider moving it.
Capitol Hill Roof Deck (well, not today): I just got two improved Meyer lemon trees (about a foot tall) and put them in 10" terra cotta pots on our roof deck to get them plenty of sun (which is in short supply these days). Will they be OK on the roof for the hot summer months, as long as I water them daily? Any other recommendations? (I'm using an organic fertilizer already.) When can I expect usable lemons off of them? Thanks very much! Adrian Higgins: Yes, do inspect them for spider mites (they make webs in the leaf joints) and if you have them you can wrap a trash bag around the pot to keep the soil intact and turn it upside down in a bathful of water. Mites hate it, the lemon loves it.
Mclean, Va.: Hi Adrian,
Enjoy your online chat and have been busy mucking around since I am redoing my yard. My question is what tall, long flowering evergreen/decidious shrub would you recommend that I grow next to a wall? The 3-feet wide bed gets good western exposure. Two Tortulsa junipers flank the two ends of the bed with pink azaleas in the front. My original plan was to have a Tonto Crepe Myrtle (love the fuschia/red color and the blooms are around for months) but I am concerned about roots growing into the foundation wall. Thanks. Adrian Higgins: I don't know that the alternatives would be any worse or better than the crape myrtle, which is an excellent choice for what it obviously a hot site. If you have your heart set on an evergreen, I would consider a Hinoki false cypress or even an improved variety of the Eastern Red Cedar, which I regard a handsome and underused native tree. You may want to widen the bed by another three feet, if you can.
Annandale, Va.: Should I cut off spent blooms of columbine? How about eupatorium and scabiosa? Adrian Higgins: I think the only one that might benefit from that would be the scabiosa in terms of prolonging the bloom period. I like to collect the seeds of the columbine to allow it to spread, but the seeds must be allowed to ripen in their pod and then scattered on soil that is very lightly mulched, if at all.
To Arlington, Re: Herbs, balcony: You'll be much better off buying seedlings and going from there. I've had great success with basil, rosemary, lavender and mint -- all in pots on my balcony. Just make sure the pots are large -- 10 or 12 inches in diameter, especially for the basil and mint. And plenty of sun is good too. Good luck! Adrian Higgins: Thanks for the advice.
Stumped in Arlington, Va.: I would like to remove a row of about 30 small trees (trunks at base about 6-14 inches in diameter) from my yard. I've dug out some of the roots (about two-hour job per tree with standard tools-shovels, etc.), but would like to have a firm dig up the rest of the trunks. However, most stump removal firms only offer to grind. What type of company can pull out the old trunks completely and turn/clean up the soil a bit to rid it of rocks/broken concrete and materials left over from builder so I can put in some nice landscaping? Thanks! Adrian Higgins: The standard way of doing this is with a stump grinder. You will be hard pressed to find anyone who would do it by hand. Grinding would also be a lot cheaper for you, since the time involved is much less. Any roots that the grinder misses will rot away in time. I would get them to grind out the stumps and then attack the area with a strong garden fork, unearthing all the rubble, etc. This is a long job, but I don't know of an alternative short of building a retaining wall and piling up new soil.
Herndon, Va.: Love these chats! Any suggestions for a shrub or dwarf tree for a shady north-west corner of my house? I would prefer that it not get much taller than six feet. The soil is mostly clay. Thanks! Adrian Higgins: I would go for a Shasta double file viburnum, or possibly a Carol Mackie daphne. Do try to enrich the soil a bit first.
Adrian Higgins: On the boxwood psyllid, the larvae of the insect feed on the new spring growth and the way to prevent this is to spray with a chemical or organic pesticide formulated for psyllid when the leaves fully open in April and again in mid May. Insecticidal soap will work. I would give the second spray now to discourage further feeding, and simply remove the cupped foliage and bag it. Make a not to spray next April.
Wheaton, Md.: I'd like to plant a large fir tree behind my house (an area with trees -- some large, some smaller, all deciduous -- and some small plants, largely shaded throughout the day). Would a fir be able to grow in such an environment? When should the tree be planted? If I want to start out with a large tree, rather than waiting for a small one to grow, should I have a professional sell and plant it? Thanks. Adrian Higgins: Firs don't like the heat of lowland Virginia, Maryland. Spruces will take it, but they are only supposed to grow in full sun, but they will actually take some shade. However, it is a tree that grows too big for all but the largest properties. The number of conifers for shade is rather limited, principally the hemlocks and yew, the latter too small for your program. I would consider American holly, a conifer called thujopsis, or maybe dawn redwood, a deciduous conifer.
Gaithersburg, Md.: Dear Adrian, I was mortified by Scott Aker's column this morning as I have willingly planted vinca (major, I'm quite sure) as ground cover near/in a bed with a rose, a holly, rhododendrons, azaleas and pyracantha. The vinca is now a year old and is starting to spread. Have I sentenced all of the other plants to doom? I would be very grateful for any insight and suggestions. Many, many thanks in advance. washingtonpost.com: Digging In, (Post, May 22) Adrian Higgins: I feel that like any plant that wanders, if you stay two steps ahead of it, it is not a problem. This morning I removed about ten new stalks of a lovely but wandering bamboo and will continue to do so until I just have the old stems left. Don't feel guilty. I think the point Scott was making was that if a vinca gets in with another plant, it is difficult to separate the two. And make sure that new potted plants are not also carrying running plants as hitchhikers.
Falls Church, Va.: Two questions: why, when a dozen or so radishes formed nicely, are all the rest bolting? They have plenty of space between them and it can't be the heat. Second, I'm getting impatient about my cannas. Is the ground still too cold? They can't have frozen, they're by the house, and even the "annual" salvias and snapdragons I planted last year are coming back. Thanks as always for the good advice. Adrian Higgins: One of the effects of this long cool spring is that certain quick bulbing root vegetables have not had the warmth and light they like to bulb up, and any root crop will bolt if it is old enough. Try again, or allow your radishes to bloom, they make lovely star like flowers. If you left the cannas in the ground, they are highly unlikely to have made it through the very cold and prolonged winter.
Cumberland, Md.: Do all perennials require dividing at some point? Adrian Higgins: Most but not all. Perennials tell you they need dividing when the flowering falls off, and also when the center of the clump becomes bare of stems so that all the offshoots form a donut.
Laughingstock, Down Under: Keep up the occasional clever ripostes, maybe people will lighten up. I luv 'em. Still chuckle about the guy with the entrenched forsythia, and you suggested he praise the Lord! Excellent stuff, jolly good show! Carry on. Adrian Higgins: Thanks Mate, And throw another shrimp plant on the barbee.
Arlington, Va.: The Garden Tip of the Week in today's Home section reminds us to cut back our mums, asters, and sedums. Could you describe "cutting back." That is, to what height should they be cut? Anything else we should know about cutting back these plants? Is now also a good time to fertilize these? washingtonpost.com: Tip of the Week, (Post, May 22) Adrian Higgins: I have cut mine back by one half, given the rampant vegetative growth this spring. Yes, I would feed them with a balanced slow release fertilizer, now and when you see the flower buds forming.
Centreville, Va.: Should I be cutting back my azaleas now -- all the flowers are gone. Thanks! Adrian Higgins: Yes, we are going to talk about this in next week's Home section.
Northern Virginia: Hi Adrian, I hope you will solve a mystery for me. I grow my tomato plants from seed and I put out three of them, healthy plants, in Tomato Teepees in mid-April. There's been no frost anyway since then. They were growing fine, but after about two weeks, I noticed that the new leaves were WHITE. I took off the teepees and waited. They didn't seem to be recovering after three more weeks, so this week I pulled them up and they had NO roots! The other seedlings I planted next to them at the end of April are healthy and growing like crazy. What happened? Thanks for your answer! Adrian Higgins: I think they were eaten by slugs or cutworms. If the remaining seedlings are not enough, consider getting young plants to set out.
Central Virginia: I decided this spring that I like pulmonaria after all, and have planted two varietes -- Little Star (two each) and Trevi Fountain (1). One of the Little Stars is looking unhappy. Some of the leaves have died and the remaining few look unhealthy. Could it be the wet weather? The other two plants are planted in the same area and look fine. Adrian Higgins: Pulmonaria loves moist soil and responds well to it. This might be slug damage. Go out at night with a flashlight and see if you can see them. If so, pick them off or put out slug traps.
Round Hill, Va.: Good morning! And HELP! I'm looking for a "screen" to plant along a three-beam split rail fence (approx 5'-5 1/2' tall) to give our family a little privacy in the back yard. Said fence is along the back side under three medium-height (20-30 feet or so) maples planted in a row, so the area gets a lot of sun from mid-fall to mid-spring, and a little sun and dappled sunlight the rest of the year. We don't want to cut down the maples to make way for something cliche like arborvitae, and ideally, I'd love to plant an evergreen shrub or vining plant that will grow quickly. We're tired of the four nose-miners/rugrats/anklebiters next door watching our every move! ...so QUICK!
And many thanks!
P.S. Though the maples have yielded fairly shallow roots, grass grows very nicely under them. Adrian Higgins: There are not that many hardy evergreen rampant vines. I would possibly plant cross vine, bignonia, or creeping euonymous. Well folks, another hour has come to a close. If you want flip answers to all your gardening questions, be here next week when we ponder the profound, profane and sacred mysterious of horticulture, such as: Can I still plant by tulip bulbs?
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