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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Waldorf, Md.: I harvested a bushel of tomatoes from my garden to make tomato sauce. I also added from my garden basil, marjoram, oregano, and garlic. I carefully chopped just the leaves of the herbs being careful not to add any stems. After cooking the sauce for about an hour, I tasted the sauce and it was extremely bitter. I had to throw it away. What do you think made it bitter? I want to try again, but I am afraid of using any of my fresh herbs. Thanks for your help.

Adrian Higgins: I have consulted with Renee Schetler from our Food section and she thinks you may have overcooked the marjoram and oregano, releasing more bitter flavors. My advice would be to try again, but add those herbs later in the process to minimize their astringency.

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Arlington, Va.: I've been having a terrible time with getting my flowers to bloom this year. Are they getting too much rain? I.e., are they too happy?

However, I am worried that the damp has adversely affected my anemones (A. sylvestris). They have gotten smaller and smaller by the week. Now there are two or three leaves coming up from the ground. It is very sad.

Early on, I suspected bugs, but the bugs seem to have backed off a bit and the anemones have not recovered.

Any suggestions?

Adrian Higgins: I think that we are having another summer of cloudy and rainy conditions that simply have reduced the hours of sunlight. I think too that our tree canopies have grown mightly in the past two years due to the rain and that this is casting more shade as well. The result is a drop off in flowering of all kind of sun loving plants.

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Arlington, Va.: I want to pull out an under-performing mature lilac bush that is along my back property line between a Leyland Cypress and my bed of perennials (black-eyed Susans, Joe Pye Weed, etc.) I'm looking for interest in more than just spring season and some screening of neighbors play set. Any ideas?

Adrian Higgins: Evergreen screening doesn't produce the splashes of seasonal color inherent in non coniferous material. I would try a handsome conifer such as Korean fir or Serbian spruce, or you might try some of the larger holly varieties. There is one called the Kohneana holly that is very attractive and grows large.

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Chincoteague Island, Va.: I live out in Chincoteague Island, Va., and lately we've had so much rain that many of our flowers which include impatience and wavy petunias are turning yellow and dying. Is there anything I can do other than hope that we get a good string of dry days?

Adrian Higgins: I rest my case.

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Washington, D.C.: Hi Adrian -
My plants are doing great, except for one thing. The flower plants (eg. miniature roses, gardenias) are not flowering and my giant (7 foot tall) tomato plant is not producing tomatoes. What am I missing?
Thanks!

Adrian Higgins: Ironclad

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Crepe Myrtle: Am I the only one with a weeping crepe myrtle? With all the rain, the blossoms are like sponges. Should I tie the branches up a bit so they don't bend permanently?

Adrian Higgins: Do some selective pruning that will cause the remaining flowering branches to arch higher where there is more light.

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Bethesda, Md.: My husband and I just spent two weeks installing 12 inch rock walls and flagstone paths and creating wonderful new flower beds. At the edge of each flower bed we would like to put a visual plant that keeps its leaves year round as the rest of the bed will be lillies, roses and flowers. The beds get sun all day until about 5 p.m.
Any suggestions?

Adrian Higgins: If you mean as an edging along the entire border I would suggest something like a small boxwood such as Vadar Valley, or Buxus harlandii, or traditional English box.

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Rockville, Md.: Hi Adrian-
I was the high bidder at a silent auction -- which allows me to go to a neighbor's beautiful shade garden at basically take whatever I want. (of course within reason) A few questions: When's the best time to do this?; What plants will transplant best (easiest), And how do I make sure I'm not doing harm to her garden?

Adrian Higgins: Curious. Perennials will move easily. With woody plants, typically, the larger and older the plant the more difficult it is to move. September would be a good time for this.

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Roanoke, Va.: Dear Mr. Higgins, Heard you on the radio in July while visiting D.C. -- loved it. Could you tell me if it's too late to cut down my huge strawberry patch, as I was supposed to do having fruiting stopped?

Adrian Higgins: You can and should remove old leaves by season's end but be careful not to damage the plant crowns or the nascent leaves that are there, which will sprout in late winter. I don't know that you need to do it now, though I don't think that would hurt the plant. Strawberries are extremely hardy.

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Alexandria, Va.: What are the best type of flowering plants to plant now, in preparation for fall? My impatiens aren't looking so hot, and I'd like to replace them with something nice (for a morning-sun deck).

Thanks!

Adrian Higgins: For an annual, you could put in some mums. For perennials, consider asters or Japanese anemonies.

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Falls Church, Va.: Good Afternoon, Mr. Higgins: My husband and I moved into a beautiful home in Falls Church two years ago, with a heavily wooded backyard seemingly perfect for my two favorite plants: hostas and ferns. I planted many dozens of hostas this spring, only to watch them literally disappear. The leaves seemed to sink into the ground, and when I examined them, the roots were completely gone. Near each plant is a hole, appx. the size of a poker chip. A neighbor tells me that I have an infestation of voles, and their favorite food is hosta roots. They do not seem to care for my ferns (thank Goodness!). How do I get rid of them? They have destroyed over $1,000 worth of hostas. Are my ferns safe, or will the little monsters concentrate on them when they have exhausted the supply of hostas?

Adrian Higgins: This is the work of voles. There is no easy remedy. I know of one hosta fancier in vole terrority who has placed hardware cloth around the roots of each plant, a laborious job. Other people ring their hosta roots with gravel. You may want to switch to other shade plants, even other ferns.

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Lancaster, Pa.: Help! Have you ever dealt with something called digger wasps? These things are disgusting looking -- they're the size of hummingbirds and have an ugly-looking stinger. Even worse, they "drill" into the lawn and leave piles of the displaced dirt on the grass. I understand they follow the cicadas, kill them, stuff them into the holes and feed on them at a later date. Do these things go away, and why are they picking on my yard? Nobody else has a problem with them.

Adrian Higgins: They are called cicada killers and yes they live in the ground. They can be present in large numbers. My impulse is to live with them, if you don't disturb them they should leave you alone.

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Rockville, Md.: Is it too late in the season to plant raspberry bushes and get actual berries? Thanks.

Adrian Higgins: THere are some fall bearing ones readying to fruit now, so yes you can plant now and get fruit. But raspberries are long term plants and you grow them for five years or more of fruiting. In other words, anytime is a good time to plant raspberries, even if you have just missed the year's fruit. It also takes a couple of years for a bush to get to a decent fruiting size.

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Washington, D.C.: I have red tipped Photinia (sp?) bushes around my back yard that have a fungal infection. Some are already dead. I would just assume yank them out and put in something more interesting. I have two questions:

How do I get the roots up?

Can I put the bushes through a chipper or will that spread the infection to other vegetation in my yard?

Adrian Higgins: I believe the blight is unique to this genus so you won't be spreading the disease to other plants. I have never dug photinia roots so I don't know how tenacious they are, or whether the shrub will continue to sprout from the roots as lilacs or forsythia will.

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East Falls Church, Va.: A lawn question: we are inundated with chicory. What does the presence of chicory indicate? Something about soil chemistry; that we cut the grass too short, allowing the weed to dominate; or something else? We don't apply any chemicals to the lawn (other than moderate fertilizer after seeding).

Adrian Higgins: Chicory grows in poor, compacted soil and prefers a high pH and a sunny site. Your lawn may need more aeration and addition of organic matter, but not more lime. I would get a soil test.

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Silver Spring, Md.: My wife and I are first-time homeowners and we are excited to finally have a yard to do some gardening in. However, our tiny yard is surrounded by some tall trees, so it is in the shade for most of the day. There's a lot of indirect light, so it isn't as shaded as a forest.

We are interested in some annuals or perennials that will do well without much direct sunlight and that are low-maintence. We are especially interested in plants that are colorful and interesting, yet easy to maintain. Are there any interesting plants out there that we should look at, or are we stuck with vines impatiens?

Thanks!

Adrian Higgins: In the shade, you must learn to find more interes and beauty in foliage. Indeed and in time, this is far more satisfying than flowers alone. I would consider things like lamium, hardy begonia, liriope and even pachysandra.

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Arlington, Va.: If I pull out all the crabgrass in my lawn now, should I put grass seed in the spaces? Or anything else? I am afraid it will just grow back.

Adrian Higgins: Yes, you must fill the vacuum or other weeds will grow there over the winter.

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Falls Church, Va.: In clearing out some overgrown shrubs, I discovered a volunteer dogwood, about 4-feet tall. I would like to move this tree to a partially shaded spot in the front yard. If I do so this fall, might it bloom in the spring?

Also, how big a root ball should I take along? The trunk is no more than an inch an a half in diameter, and the branch span is about 4-feet.

Thanks!

Adrian Higgins: The flower buds for next year will be forming now in direct relation to the health of the plant and the degree of sunlight it receives. I would move it in September and while it may not bloom heavily next year, it should in ensuing years if you give it a modicum of sunlight and deep rich soil. Be conservative when digging it, and dig as large a rootball as you can handle, I would say 30 inches or more in diameter.

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Woodbridge, Va.: Adrian... hello!

My question concerns landscape architect services. We've recently had to take out several foundation plantings as well as a decorative cherry tree (all diseased) around our ranch-style house of almost 30 years. Our plantings are ad-hoc, decidedly amateur, and otherwise something less than comprehensive. I'd like to root out some lilacs as well and secure the services of a landscape architect to make the whole at least equal to, if not more, than the sum of the parts. My wife is skeptical of value of such an expense, but I think the sloping side yards (we have a walk-out basement) can be enhanced by the skills of a professional designer. Would appreciate your take on this issue, if you're so inclined. Thanks much!

Adrian Higgins: I once gave someone the name of a top local designer and he complained that she wanted $150 to visit the site and produce a conceptual plan. This is how much one might spend on getting a lousy sapling planted. The value of good design cannot be overstated.

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Fairfax, Va.: Dear Mr. Higgins,

I have a Holly tree that is healthy looking, growing taller every year, but not fuller/bushier. What can I do to make it look/grow a little fuller? Thanks.

Adrian Higgins: Depends on the holly variety. Some are meant to be pointy. Others take shearing well.

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Arlington, Va.: Good afternoon! What kind of plantings (shrubs, trees, etc.) will give me glorious fall color? And is it too late for this fall? Thanks!

Adrian Higgins: Lots of good stuff: Sourwood, Japanese maples, blackgum trees, Asian persimmons, fothergillas, witchhazels, viburnums, sumacs.

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Linden, Va.: Hi Adrian,

We live on a mountain with a noisy highway below. We are planting bamboo to use as a noise and lousy view screen. Although it will take a while to grow to its potential, how do we know when to cut it back or which ones to thin out if it gets too thick? Thanks

Adrian Higgins: I would advise against bamboo. It will develop into a thicket that will plague the site for decades. I would plant a buffer of trees and large shrubs, starting with a massing of conifers and proceeding down in scale with plantings in front of them. You need the buffer to be thick for the sound proofing to be effective.

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Shaker Heights, Ohio: Adrian, is it bad to grow shrubs in a thick bed of pachysandra? Our pachysandra is thriving, but the rhododendrons the previous owners planted in the bed are spindly, a little yellow, and didn't even bloom this year. Wondering if it is the pachysandra. The azalea doesn't look so great either.

Thanks.

Adrian Higgins: The root system of the pachysandra is unlikely to offer such competition, though the presence of a ground cover would lead me to make sure the shrubs have a nice top dressing each year of rotted compost. I suspect your rhododendrons are ailing for other reasons, and may be chlorotic from high pH and insufficient iron.

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Arlington, Va.: Good afternoon. Could you suggest some perennial herbs or other small plants to plant between flagstones on a garden path? The area is semi-shade.

Adrian Higgins: If the path gets moisture as well as shade then I would go with Mazus reptans or creeping jenny.(two different plants)

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Silver Spring, Md.: Is there such a thing as a low-maintenance yard? I inherited a yard with lots of bulbs, a lilac bush, tons of azaleas, hostas, daylilies, and my nemeses: tenacious grapevines, english ivy, and a nameless vine that threatens to overrun the whole property. I find myself pulling vines, deadheading, and trimming every weekend. I hate the azaleas and want to rip them out, but aside from the lilac bush, they're the only substantial year round plants in the yard. Can you suggest something to replace them? The area is mostly shady/partly sunny with the usual compact clay soil. Thanks!

Adrian Higgins: It seems that before you consider the level of maintenance in your yard, I think you must first undertake the exercise of ripping out vines and pulling overgrown shrubbery. This is something quite different from ongoing maintenance. With a lawn and conifer plantings, it is possible to reduce the level of care needed, but there is no yard and there is certainly no garden that requires no maintenance. Anything you read or hear to the contrary is a lie.
Also you cannot have a glossy-magazine-style English garden without making it your hobby.

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Middletown, Md.: Is there a public garden in the area with a good collection of Japanese Maples? And do you have a favorite variety? My boyfriend and I want one as a feature in the front yard, but are having trouble deciding on a variety. The discussion is getting very... lively. He likes the little mounding kind, I like the larger more tree-like, he likes the ones with very skinny leaves, I like the less skinny leaves.... you get the picture. We need help!

Adrian Higgins: Good question. I would try the Asian Valley garden at the National Arboretum.
The best Japanese maple nursery hereabouts is called Eastwood Nurseries in Rappahanock County, Va. I don't have a number to hand but you might be able to Google them.

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Annandale, Va.: Dear Adrian,

I am heart broken to find the red oaks in my yard in so much trouble. One is nearly de-nuded of foilage, and a near-by one seems to be going down the same path. The borers have a two year cycle and I have not been able to determine where they are in their cycle, if in fact the majority of damage is behind them or in front of them.

There are also carpenter ants. Please tell me Adrian what application must I go to buy to treat the trees? What must I ask an arborist to determine whether the tree must come down or not? Do I treat the white oaks and other trees that do not appear to be affected? Signed, Those who must write for the trees, as they have no tongues of their own.

Adrian Higgins: Red oaks tend to be more disease prone than white oaks, and are facing some unhappy ailments these days. Borer damage tends to follow some other stress. I would get a good arborist to see what is ailing them and treat both the symptom and the underlying cause. The very best thing to plant under a tree? Mulch. Trees in lawns do not do well, often because the turf is treated with a fungicide that kills the beneficial microbes that the trees need to flourish.

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Central Virginia: Hello! I wrote a little while ago, asking for advice about Japanese beetles on a rose mallow, and I've discovered something that may help other people.

Since a rose mallow flower is trumpet-shaped, those pesky beetles often climb right inside the flower and start eating from that end. And since they have those nasty, spiny feet, and a rose mallow's petals are very tender and fragile, fetching a beetle out to squash it can be as destructive to the blossom as just letting the beetle chomp away.

So I have discovered that if you gently squeeze the base of the flower, the beetle gets alarmed and clambers out so that you may pick him off and squash him at your leisure. Works great!

But you have to listen carefully when you start to compress the flower base -- an indignant "BzzzZZZZZZZ!!" means that you've interrupted a bee in the middle of a nap and she does NOT appreciate being pinched! It seems that bees love to sleep in rose mallow flowers; they're so funny! I've counted half a dozen at a time, and even enormous bumblebees will wedge themselves down inside a flower and snooze away.

Regards!

Adrian Higgins: Bumble bees good, Japanese beetles bad.

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Rockville, Md.: Where can I find seed garlic locally? I know I can use the stuff in the grocery store, but I would like to try some different varieties.

Adrian Higgins: You may have a hard time finding seed garlic locally. I would check with mail order catalogues such as Seed Savers or Territorial.

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Petworth, Washington, D.C.: I read this week in The Post that the cicada larvae will soon be dropping out of the tree branches where the adults laid eggs earlier this year. I'd thought that it already happened.

I've got a young maple tree in a tree box in front of my house, and its very apparent from which branches the cicadas will be dropping. Would you recommend clipping those branches? Should I do anything special about disposal?

Adrian Higgins: No. If something has to live 17 years in the soil, give it a break.

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Rockville, Md.: Have you, or any of the chatters, seen an Osmanthus fragrans (sweet olive) for sale locally?

Adrian Higgins: I have only seen it growing at the National Cathedral. I don't know if local nurseries carry it becuase it is considered marginally hardy here. I would check with a mail order nursery such as Heronswood or Joy Creek or Fairweather Gardens.

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Lanham, Md.: Thank you for answering questions. I learn a lot from your book, articles and online chats.

I have a question about the blueberry bushes I planted two years ago. I have been getting only a few very small berries on each plant. Before planting, we dug 2-feet diameter holes and mixed soil with lots of manure and peat moss. I read that I am suppose to cut all over-3-year-old branches because they only fruit on younger ones. However, I have not done any trimming yet because I cannot tell which branch is older than 3 years. How can I tell which branches to trim and what can I do to get more & bigger berries?

Adrian Higgins: I think you would remove the older branches for another reason: to allow more light into the bush. This will improve fruiting. Older branches are darker and with a much more pronounced bark texture. And thicker, of course.

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Fairfax, Va.: I have a small backyard with multiple large and small potted plants, herbs, veggies and bonsai trees. But lately the squirrels have been ravaging my potted plants, especially the sensitive bonsai trees, by digging in them, chewing them and knocking them over, which results in dead and injured plants. Please help me, is there anything that will keep the pesky squirrels off and the plants healthy?

Adrian Higgins: I think they are looking for places to bury nuts for the winter. I don't know if it is too late now but you could lay netting over the soil. Obviously this is much easier to do when the pots are first planted, something to remember next May.

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Washington, D.C.: I put in my vegetable garden late -- at the beginning of July. The butternut squash and zucchini have been growing beautifully for the most part, though a few of the leaves have been eaten and/or are rather yellowy (I'm not using any pesticides). I'm more worried that a lot of the flowers (blooming for a week and a half now) have been falling off, and only a couple seem to be setting fruit. Is this just because of all the rain we've been having? It seems rather wet under the leaf canopy.

Adrian Higgins: Again, things are behind due to the rain and cloud. We still have a month of summer weather and (let's hope)a good old heatwave. Don't give up on them yet. Alas, I must go. Thanks for all your questions: See you next week.

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