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 Washington Post)
TIP OF THE WEEK (The Washington Post, Apr 8, 2004)
Plant Potatoes? The Eyes Have It (The Washington Post, Apr 8, 2004)
Beyond the Tidal Basin, There's a Cherry Jubilee (The Washington Post, Apr 8, 2004)
Easy-to-Grow Flowering Trees (The Washington Post, Apr 8, 2004)
GARDEN DATEBOOK (The Washington Post, Apr 8, 2004)
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.
Adrian, a plant mystery that you can hopefully solve for me.
Years, and a couple of houses, ago I bought a shrubby plant at a small nursery that no longer exists. It had long spikes and bloomed with the most beautiful pinkish flowers. They told me the plant was called "French Broom."
In trying to find and secure one again -- it was beautiful -- I find info on the Web that says French Broom is an invasive non-native plant. But, worse than that, in only describes it as having yellow flowers.
Was my beautiful pink plant not a French Broom? If not, I wonder what it was... Help!;
Adrian Higgins: Broom is a short lived shrub that demands really well drained soil and a perhaps some shade to survive here. It does well in more cool temperate climates, here it tends to peter out quite quickly. This is a shame because it's a great vertical accent in the border, both in bloom and with its fine textured foliage. There are many many different varieties, most yellow, some pink, some lavender, some bicolors. The botanic name is Cytisus and a popular variety is the Warminster Broom, which is actually a hybrid Cytisus x praecox with a number of different cultivars. Worth treating perhaps as a short lived perennial in our clime.
Falls Church, Va.:
I read recently that coffee grounds are good for adding nutrients to soil and to include in compost. My question is, if I work it into the soil in my beds, are there any plants that I shouldn't plant there because they will be damaged by the added acid? Thank you so much for your help -- I read your articles and chat every week and I can't tell you how helpful they've been to me.
Adrian Higgins: Most garden plants grow in soil that runs the range from pH 5 to 7, that is somewhat acidic to neutral, and that tends to be the chemistry in our native clay soils. You might only fear putting coffee grounds or any other slightly acidifying matter on plants that we know need a neutral to alkaline soil, such things as lavender, rosemary, boxwood, members of the cabbage and onion families. It is best to compost individual things like coffee grounds, so that the finished mix is tempered within itself.
Hi! I planted three Coral Bells azaleas last year in a row along my shed. One looks fine; the other two have gone dry and crispy, although there is some green on both (and even a few flowers on one). What can be done to save them? Do I prune the crispy branches? When? Many thanks. Love your chats!
Adrian Higgins: Don't know. The single most important thing for a shrub like azalea, which has very precise cultural needs, is soil preparation. It needs acidic soil that retains moisture and yet drains, virtues achieved through the addition of organic matter. Most azaleas also benefit from afternoon shade. Don't choose a site for a plant, choose a plant for a site. It is also important to know the variety or type of azalea so that you can plan for its eventual growth in locating it.
Adrian, I have a young plum tree that I planted one November about five years ago, and it's only now beginning to fill out and look like anything. Should I cover it to protect it from the cicadas? I have some spun floating row cover garden fabric and some clothespins --should I loosely mummify my tree until the 4th of July? Thanks.
Adrian Higgins: No, just leave it alone (this may come back to haunt me of course). I am writing about this topic is the next Home section. Your tree should be old enough to sustain a cicada attack. If you wrap a tree in anything other than netting, you will end up doing more harm than good. A scientist I talked to said his experiments with cheesecloth wrapping showed that he had trapped within a plant populations of really harmful pests like mites and aphids which simply multiplied out of control because their natural predators could not get through the cheesecloth to kill them.
I love Provence lavender, and have had a couple of summers when it's come in beautfully. Much of it has since died out although it gets excellent southeastern light. I suspect the winters have been too harsh for it. Is there something I can do to protect it, such as mulching or covering it with straw in the fall? Also, when would be a good time to plant a new crop this year?
Adrian Higgins: This is one of the Lavandin varieties, big flowered but tender somewhat. They will make it through a normal Washington winter but only if they receive excellent drainage around the crown of the plant. Put one in clay soil and kiss it goodbye. If yours has died, it is worth replanting, I suspect if they can get through a couple of winters they develop more hardiness, but don't mulch them with organic mulches in the winter. Just use a lot of gravel and grit in planting and mulching them.
Are there any trees that lend themselves to container gardening and if so what are the watering, container requirements?
Adrian Higgins: A few. Dwarf conifers like Japanese black pine and Hinoki false cypress are good candidates. I have seen magnificent Japanese maples in containers. The key obviously is lots of room for the roots, very good drainage, and a commitment to watering in summer, one good soaking a week at least. You may also need to lift a tree every few years to prune the roots and replenish the soil.
Hi Adrian, I was thinking of planting epimediums as a ground cover over a shady patch of my garden. I was just wondering whether this was a good choice or if can i find something better suited for a shady spot. Thanks!;
Adrian Higgins: This is a superb choice. The delicate flowers and followed by wonderful clean arrowhead shaped leaves. The plant seems unaffected by pests and diseases, can tolerate dry shade, and flourishes in our climate. But you must be patient. It takes five years for a plant to fill out and for a massing of them to look the business.
I'm so glad your Q & A session is back! I planted hostas two years ago. They first year they looked great but when they came back last year they were much smaller and not nearly as full. Does this take time or am I doing something wrong? Actually I didn't do much to them except ensure that the automatic sprinklers hit them, sprinkled them with time-release fertilizer and mulched around them. Thanks for your advice.
Adrian Higgins: No, they shouldn't be getting smaller, especially in a year of record rainfall when they should have been much largern than normal. Maybe your soil isn't rich enough or they need lifting and dividing. If you think they don't need dividing yet, I would give them a regular feed of liquid kelp or fish emulsion, which should also deter slug feeding.
New homeowner in Grass Panic:
Hello! I am a proud owner of a small condo with a backyard (roughly 10 x 10). Once spring hit, the weeds and grass started growing out of control and I need to get rid of it. But I don't know what to do. I don't have much money and am afraid pavers will cost too much. I have no room to store grass cutting equipment and really need an affordable way to remove the grass and replace it with something (mulch?) so I can container garden. Any ideas for a house-poor newbie?
Adrian Higgins: Unless you dig out the grass, you will have to mow it. I think I would save my pennies and plant a range of ground covers in the fall. Meanwhile, consider digging up the patch, working in lots of bags of compost and peat, and buy cheap flats of annuals such as cosmos and cleome. Get some seed of sunflowers and grow those. You will need to water and weed your little cottage garden but will have loads of butterflies and bees and hummingbirds, perhaps, to enjoy this summer while you plan a more permanent arrangement.
Del Ray, Va.:
Help! I got some rose bushes from a friend whose apartment building was tearing them out to plant something new -- we tried to get as much root as possible, plant quickly and amend the soil, but they're pretty droopy. Should I cut them back? Or just leave them and hope for the best? I'm watering them every night, is that right? Thanks!
Adrian Higgins: Stop watering them, you will kill them. Cut back the top growth to about 18 inches. Hope they resprout, which they may well do. You will miss the June show of flowers but they may come back for the September one.
Out of curiosity, I tasted the sap that is oozing out of the peony buds in my yard. It wasn't very tasty, but surprisingly identifiable -- like a syrup formed from sugar and an infusion of broccoli. How does this substance assist the peonies in their reproductive goals -- do the ants that are attracted to it help spread the flower's pollen?
Adrian Higgins: I think they do. Thanks for tasting it, that means I don't have to.
I put down grass seed about two weeks ago, was very good about watering it, and getting good contact with the soil... and nothing. It was quality seed, and I can see most of it still sitting there. Is it dead? Bad? Should I put more down? Help.
Adrian Higgins: Tall type fescues take a couple of weeks or more to germinate. Give it a couple more weeks. Plan to reseed in September.
Adrian, how did you get so interested in plants and gardening? Did you study gardening in school? Or journalism. Just wondering how you acquired your encyclopedic knowledge.
Adrian Higgins: I started out as a journalist. I considered becoming a landscape designer and went through the Landscape Design Program at GW, where I learned design and some horticulture. I decided instead to combine my two passions and become a garden writer. Most of my horticultural knowledge comes from reading, interviewing experts, and doing some serious gardening for the past 20 years. I find I learn two new things every day and then forget another. On balance, there seems to be an accretion of knowledge.
Unfortunately, like many Washingtonians, the alley abutting my backyard has a rat problem. Is there anything gardenwise I can do to discourage them from coming into my yard?
Adrian Higgins: Don't keep a compost pile or allow brush to accumulate. I'd call the city rat control office.
Logan Circle, Washington, D.C.:
Adrian, hello. Most of my beloved Siberian irises vanished over the winter. Any guesses why, or advice on what to do next year if I decide to give them another go? Thanks so much.
Adrian Higgins: I can't imagine why, they like it wet, which it was last year, and as their name indicates, there is no winter too cold for them. I'm at a loss. Does anyone else have any ideas?
For the past two years, when pulling up bush beans, I have discovered clusters of tiny insects on the roots of the plants. They are white and look like aphids. They only seem to appear on beans. Do you know what they could be? They don't seem affect the productivity of the plants.
Adrian Higgins: THese may not be insects, but nodules that the bean, as a legume, develops to fix nitrogen.
To new home owner with grass patch:
For a lawn that size, you don't need to buy a big mower. You could get one of those hand held edger things that I see proffessional mowers use on the side of the road (I don't know if it is called an edger, it is a wand that has a fan of blades that measure six inches across -- I see people use it to cut grass close to trees, etc.) That shouldn't take up too much room.
Adrian Higgins: Thanks, is this like a string trimmer but with a fixed metal blade? The problem with either (or indeed an old fashioned scythe, is that unless you are very good at it, you will cut some patches too short and they will become stressed. When I was a kid, my brother cut my hair this way, and I had to go to the barber to get it fixed.
I was pulling the onion grass out of one of my beds and decided to pull up the weed barrier (the black meshy sheet that we laid under our mulch last year to stifle the weeds) and sure enough there were about -- no exaggeration -- 25 large, somewhat hibernating cicadas. At least they looked like cicadas from the 10 seconds this sight took to register before I abandoned my onion grass pulling and ran into the house screaming (again, no exaggeration, I am a wimp.) I guess my question is, we laid that weed barrier all around our beds. Will the cicadas be trapped under there? Is that a bad thing?
Any tips on pulling up onion grass, while I have your attention?
Adrian Higgins: The cicadas will be trapped under your barrier. They have waited 17 years for this moment, and you are preventing them from attaining their destiny. For 17 years, they have nibbled together on tree roots, enduring the hardships with the knowledge that one day, they would smell the fresh air, feel the warmth of the sun on their bodies, experience the thrill of flight, and of true love. If you leave the weed block down, these cicadas will never live their dream. But you be the judge.
Can you explain which varieties of lawn grasses do the best in this region? My yard gets full sunshine and foot traffic from children. Also can you explain the pros and cons of grasses that are rhizome forming vs. clumps?
Adrian Higgins: I have never beena fan of zoysia grass, which is an option for you in Fredericksburg. The best all round grass is turf type tall fescue. It is far less weak than Kentucky bluegrass, which used to be the gold standard of turf. Bluegrass does spread by stolons, the fescue does not, but I would still recommend growing fescue over bluegrass. There are many good varieties bred for the Southern climate, including those with Rebel in the name. But September is grass sowing season so be patient.
Silver Spring, Md.:
Recently, I planted a young cherry tree and six firepower nandinas, along with a vegetable garden. My property also has mature trees, rose bushes, azaleas and euonymus shrubbery. I'm concerned about the emergence of the cicadas and damage to my trees, shrubs, and garden. I know my property is full of cicadas because during spring planting we found a number of them in the dirt but didn't know what they were until recently. What can we do to protect our cherry tree, nandinas, azaleas, roses, and garden? I've heard that placing netting over trees and shrub may help, but if the cicadas are out for six weeks, is it okay to keep the netting on that long? Another odd suggestion I heard was to wrap aluminum foil around the tree trunk to keep cicadas from crawling. Thanks for the advice!
Adrian Higgins: Cicadas lay eggs on branches that are about the size of a pencil. I don't know how you would wrap woody plants with foil to every branch, and if you could, it would look dreadful. I would net the cherry tree and forget about the rest. There are ways of patrolling the garden to minimize damage on woody plants whose branches you can reach. Any damage received can be pruned out later this summer.
Sticks, Mt. Airy, Md.:
I got two tomato plants, a Roma and a Lemon boy, Can I put them in now or should I just harden them off in the pots (placed next to house) until May?
Adrian Higgins: I would harden them off by placing them in a shady spot outside, bringing them in at night for a couple of weeks. Make sure you keep them watered to avoid wilting.
I have discovered a small patch of lily of the valley growing on the side of my house. Unfortunately, it is growing right next to and in the crack crossing the back gate. I can't imagine that anyone put it there on purpose. Can I move it? How? What is a good location? (This location gets direct sun all day but I am not sure what other standout characteristics it has.)
Adrian Higgins: You can either dig them up after they finish blooming, or mark the spot and wait until they recede in September. Dig up the pips and replant them in the fall.
My dogwood is in bloom, but there are branches on the tree that are clearly dead: no leaves or blossoms and they break very easily. Will it hurt the tree if I cut the dead areas off? Should I have pruned it? Do some dead branches mean impending doom for the rest of the tree? Thanks!
Adrian Higgins: You should definitely prune out dead and diseased wood, but you may want to wait now until after flowering because you may want to remove some blooming branches to maintain symmetry. It doesn't necessarily mean the tree is dying, but it could do. Dogwoods have a blight called discula that gets into the vascular system of the branches and will advance into the larger branches if left unchecked, so you need to prune out the dieback back to clean wood. Thanks for all your questions. Same time next week.