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)
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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.
Last summer my rudbeckia grew extremely tall and leggy. Would cutting it back now help prevent this from happening again this year? It is already more than a foot high. Many thanks.
Adrian Higgins: Rudbeckia is about four weeks away from blooming. If you were to cut it now, it would be bushier but flowering would be delayed by weeks. I would cut it back after it flowers, this may promote some reblooming in September.
I was asked last week whether dendrobium flower stalks should be removed after flowering. I don't grow them but from what I have read, the answer is, yes. Earlier this summer (yes, I know it is not summer until June 21, but it has been a beastly hot late spring and I am going to call it a summer. We have been robbed of a pleasant, temperate lead up to summer and I intend to complain to the highest authorities about this...) Where was I?, oh yes, earlier I was asked if there was any good fuchsia for our area and I said no. I am trying out the variety named Gartenmeister this summer, which I am told does endure the Washintgon heat and humidity and draws hummingbirds. I will report back.
Great chat. At what time of year would you recommend aerating a lawn, and how often should it be done? Would it make sense to wait until fall and aerate before overseeding, or can it be done now? Thanks.
Adrian Higgins: You can aerate at any time, however, if you really want to make your lawn the envy of the world, you should aerate in March, backfill the holes with compost, overseed the lawn, and water. This should be repeated in September. If you keep doing this, your lawn will be fabulous.
Last Sunday we planted a 3-foot high Japanese Maple tree in our sunny front yard. We left it in the burlap sack it came in (from Home Depot), surrounded it with three bags of top soil, and topped it off with a bag of mulch. Were we correct in leaving the sack on, or should we dig it up, remove the sack and replant it? Thanks.
Adrian Higgins: If you mean the burlap that surrounds the rootball, that is planted with the shrub or tree. It rots away. HOWEVER,this burlap is gathered and tied, sometimes with nails, at the crown of the plant. It must be untied, and the trunk freed of the material in order to prevent future girdling. If you have not loosened this, go back and do so.
Is it too late to plant strawberries? Are there any kinds of strawberry that I should avoid?
Adrian Higgins: Strawberries are fruiting now. You can plant them, you may not have any more fruit this year but you will have great fruit next year if you give the plants good soil and keep them free of slugs and drought. I like alpine (frais de bois) strawberries for their tartness.
My phlox were very healthy this year, so much so that they look like giant green mounds (the flowers are gone now of course) that are overstepping their bounds onto the sidewalk. Can I trim them back in some way (perhaps just a quick weed whack?) I don't want to adversely affect the flowering next year.
Also, I am happy to report that my olive tree is still alive after a year of residing inside in a container (despite your prediction of a quick death in our zone), although it appears to have some sort of infestation. Its leaves have very small spots of a brownish tan dust that rubs off easily. Say it ain't the beginning of the end...
Adrian Higgins: I would keep the foliage intact, they are meant to creep. I doubt the olive will flourish for much longer. You may prove me wrong. Keep us posted.
Mr. Higgins -- I own a townhouse on Capitol Hill and have done a lot of work to improve the 20 x 40' front yard (a large front yard for a townhouse on The Hill). I am looking for some smaller perennials to spruce up the front of my yard. I need to get some ground cover (I'm tired of putting lots of mulch to cover the blank spaces) and some low plants that can tolerate mostly full sun. Any favorites to share?
Adrian Higgins: I would try some of the low growing sedums, along with dry loving perennials such as perovskia and agastache.
Silver Spring, MD:
Good afternoon all. Adrian: Can you recommend a flowering large bush, or very small tree, with a relatively long flowering seasonthat does well in partial sun? Ease of maintaining and native/
indiginous species would be pluses. Colors don't matter. I just don't have full sun anywhere, so lilacs (my favorites!;), etc are out. Would some kinds of climbing roses work? Thanks for your advice.
Adrian Higgins: Probably clethra, Virginia sweetspire, would fit the bill.
I have some daffodils that did not do so well this year. Lots of green, but only two blooms. I am assuming they need to be separated. Is now a good time to do this? If not, when?
Adrian Higgins: I would do this in about another two or three weeks. You can either replant them then (enrich the hole with humus)or lift, store them, and replant in September. Find a sunny spot.
Silver Spring, Md.:
Love your column, and hope you have time for my question. I recently transplanted a very large azalea, supplementing the soil. I've given several deep waterings (five gallon buckets) about every five days since moving it, but the poor thing still looks droopy and the buds, which were on the verge of blossoming, have dried up. Is it in shock? Is there anything I can do to help this beauty survive? Thanks!
Adrian Higgins: Plants are best transplanted in their winter dormancy, even evergreens. I would neither overwater nor underwater the plant this summer. You may want to spray it with a light horticultural oil to kill lace bugs, make sure you get the underleaves, and feed it a little liquid iron.
A couple of our hostas have a lot of dead and rotting leaves (the ones closest to the ground) can we just trim them up to look better?
Adrian Higgins: Hosta leaves should not be dead and rotting at this point. I would lift a plant and see if it has any roots. If it doesn't you might have a problem with voles.
My Peonies have finished blooming. Do I:
1. Dead-head the spent blossoms.
2. Cut them back.
3. Leave them alone.
Adrian Higgins: It's always good practice to deadhead the faded blooms, this tends to keep the leaves looking cleaner through the season.
Silver Spring, Md.:
Have any ideas why two apple tree would suddenly have their leaves turn yellow and fall off?
They had blossoms -- the leaves were nice and green and thick -- and now they are turning yellow and dropping (like leaves!)
Cicada free zone -- so I can't blame the red eye monstors.
Adrian Higgins: This maybe a blight named cedar-apple rust. Remove the affected leaves and spray with an appropriate fungicide. Apples will naturally thin their nascent fruit clusters at this time of year.
Hi Adrian! I have a question about plant leaf colors. A lot of my perennials don't produce the leaf color I expect. My purple palace Heuchera has produced more leaves with a greenish cast that the dark purple it had when I purchased it at the nursery. I have the same trouble with my Hostas. A pineapple upside down cake Hosta fades to chartruese but never develops the dark leaf edges promised. This year, my Frances Williams Hosta is a medium green with no chartreuse at all. Is this related to light conditions alone or possibly soil conditions? Thanks.
Adrian Higgins: Many purple leafed plants color up as billed but then wash out on account of our heat, which affects plant metabolism. The same plants farther north are wonderfully dark in hue.
I think I'm getting the run-around from our landscaper. Sod was put down nearly six weeks ago. We have an automatic irrigation system, so it's getting plenty of water. (Maybe too much. He insists we run it twice a day and the yard hasn't been dry all month.) We haven't even mowed it yet. But you can see empty patches in nice, neat lines between the rows of sod. Should there really be three inches of dirt between some of these rows? Or was it just not installed properly?
Adrian Higgins: You live on the edge geographicaly for cool season grasses and it maybe that the subsoil wasn't adequately prepared or the turf wasn't rolled after laying to form a good contact between roots and soil. Before you have someone do this, you should establish what will happen if the sod fails, i.e. who pays to fix it.
Georgetown, Washington, D.C.:
Adrian, dear, please help! I am having a terrible time with euynomous shrubs in my small, fenced garden. Along the back of the shrubs, the side facing the fence (there is about 12-inch clearance), leafed out beautifully this spring and then, whammo, the leaves started looking like they were wilted, collapsed, dryed, and then the stems went, too. The front half of the shrubs are still OK, but I've pretty much lost the back. The same thing happened to some euyonmous in that spot last year. It's not the soil, that's been tested, and most other things in the garden are doing fine. The symptoms sound like scale, but I don't see any bugs on them. I know you might say to try something elese, but I really want eunyomous for this spot. Your diagnosis, and advice, please.
Adrian Higgins: Euonymous scale is quite distinct, the females are brown but the males have a conspicuous white covering so you should be able to see them. Have another look and examine the underleaf closely. I wonder if the plants are salt damaged from deicing materials?
When are they going away? My garden is languishing because I don't want to go outside.
Adrian Higgins: Don't worry, the political season will soon be over.
I am going to help my son in Eastern Market with his postage stamp front yard. I need ideas for hardy, low maintenance plants that will prosper with little attention. He travels a lot. We plan to do soil preparation next week but actual planting will not take place until August due to traveling schedules. What do you suggest?
Adrian Higgins: Again, rock garden plants like sedums, agastaches, dianthus and penstemons make good candidates for areas of neglect.
Falls Church, Va.:
I'm a new home owner/first time gardener who desparate doesn't want to kill ALL her plants!
Do you have any suggestions for so "easy" plants? How often do I water plants? Right now I have tomato plants, herbs, impatiens and hostas?
Adrian Higgins: Different plants have different needs. Many herbs come from Mediterranean and Asian climates so they do best with very well drained soil. This can be created through raised beds and giving them a good mulch of gravel. Tomatoes like rich soil and even moisture, as do impatiens, but in a shady spot, and hostas like lots of water. Generally, rich, deep soil retains moisture and doesn't need watering as much.
Upper Marlboro, Md.:
I have a few climbing Hydrangeas, as well as one oak-leaf Hydrangea and a couple smaller ones. They are just getting ready to bloom. Do they need to be fertilized? If yes, how often?
Thank you so much!
Adrian Higgins: Annuals, as I say in today's Home section, do need feeding but woody vines and shrubs don't really need a lot of nutrient as long as they are in good soil. The use of high nitrogen fertilizers can induce growth that attracts aphids and other pests and diminished flowering, so be careful. I muchprefer to lay a mulch of compost on woody plants, this will give them the microbes they need to flourish. Obviously, if you see a shrub yellowing from lack of iron or acidity, you need to address that.
Hi Adrian -
I have two questions: I had a tomato plant that I had started from seed snapped in half last weekend when the wind launched my sweet pea pot into it -- it still has two small, bottom branches, and was recently put in a larger pot (I'm saving these to take to my grandpa in Jersey next month). Will it be able to grow anymore?
And two, every time recently that I've put in marigolds, usually with the tomatoes in a large container, the leaves start getting all spotty and the plant eventually dies. I'm not seeing my usual pests like aphids and spider mites, and I thought marigolds were pretty hardy to bugs -- any ideas?
Adrian Higgins: I am not sure about the marigolds, I wonder if they have a viral disease. The tomato will grow back.
This morning in my fenced-in vegetable garden I discovered a hole where something had tunneled into the garden. It was large, almost the diameter of a tennis ball. It seems too big for a snake. Do rats tunnel? None of the plants are bearing veggies or fruit, yet, but what am I dealing with here?
Adrian Higgins: Could be a rabbit or a chipmunk or a rat. I would dig a trench around your vegetable garden and insert hardware cloth.
Capitol Hill, Washington, D.C.:
Is it too late to plant rosebushes on Capitol Hill? I'd like to put them near the edge of my small plot, to grow into the chain link fence. I want a fragrance. Also, I do not have full sun, but instead partial sun, maybe for 5 hours a day. Are some roses still ok to put there or do you have a better suggestion?
Adrian Higgins: Roses can go in, they are blooming now. After flowering, remove the faded flowers: modern hybrids will bloom again in six to eight weeks.
This is my second summer of gardening, using pots and planters on a patio. I managed to grow some lettuce this spring. I've learned that fall is also good for growing lettuce. Do I try to save the spring's lettuce plants for the fall? Or do I start a new batch of plants from seed in the fall?
Adrian Higgins: Directly sow seed in August. Thin as the seedlings emerge. You will need to do this probably twice, you want the seedlings to be about four to six inches apart. Use the thinnings for salad. Head lettuce works better as a fall crop here, the heading occurs as the days are getting cooler.
I appreciate the knowledge that you share with us. Last fall, I moved to a new home which had a 6-8 foot tall butterfly bush. Although it is currently showing plenty of growth, two of the main stalks seem to have died during the winter. Is there any special care for this bush that I should be aware of? Also, should I prune this plant annually? If so, during the fall, winter, or spring? Keep up the good work and thanks once again.
Adrian Higgins: Butterfly bushes respond well to cutting back, nay, they demand it. You cut back when it is dormant in late winter. But I cut back stems to about half their height during the spring. I do this at least twice to promote bushiness. After they bloom, you can cut them back again, this will promote reblooming in September and October.
We recently planted an already-flowering hydrangrea in our very sunny yard. Now we cannot seem to water it enough. We water it very thoroughly before work, but by the time we get home it is pathetically wilted. Are we doing something wrong? Thanks!
Adrian Higgins: First of all, the root system probably is no match yet for the top growth. You also have to make sure that roots are properly uncoiled at planting time. Also, the soil has to be nicely amended with organic matter to allow it to retain moisture. Some gardeners will cut back a shrub when planting to speed its establishment. This may cost you blooms at first but may make the difference between a plant that makes it or not. I am afraid our time is up once more. Enjoy those cicadas.