The Garden Plot

Gardening

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.

_____________

Annandale, Va.: We recently set up a compost bin in our yard. Within days, some small animal had tunneled its way under the side of the bin and was eating the contents. (The bin is an "Earth Machine" -- looks like a plastic barrel; you put stuff in through the lid.) We tried making a ring of bricks and rocks around the bin, but the critter still easily finds its way in, by tunneling where two bricks come together. I don't know what kind of animal it is (tunnels are about 2" across), but I don't think we want to encourage it. Any suggestions? My husband thought we might set the bin on a slab, or a layer of bricks -- might work, but the manufacturer thinks it should be in contact with the ground to encourage earthworm activity. Thanks!

Adrian Higgins: It might be a vole or a mouse, or even a chipmunk. Short of creating some sort of barrier that goes down a foot or more, I don't know how you might prevent this. Rodents look for shelter and food at this time of year, who can blame them?

_______________________

Silver Spring, Md.: Help! My new front yard has a wondrous, otherwise-healthy-looking tall tree with sawdust trailing down the bottom foot or so of the trunk. What might be causing this and what should I do? Someone mentioned carpenter ants and the risk of them crossing over to my house -- sounds scary and harmful!

Adrian Higgins: This is probably a borer insect and yes, you should be worried about it, because the creature is damaging the plant. One simple way to kill the pest is to poke the hole with a straightened paper clip. I believe carpenter ants are drawn to wood that is already rotten, i.e. dead.

_______________________

Washington, D.C.: My neighbor has kudzu. It's a rental so I climbed the fence, cut it down, dowsed it in Round up and now, one year later there is new growth! HELP!

Adrian Higgins: I wouldn't rely on herbicide to get rid of kudzu. I would pull it, both now and when it emerges in the spring.

_______________________

Montgomery Village, Md.: Hey Adrian, I've had some Virginia Creeper show up in my yard. It's in an area that I would not mind some ground cover and it is kind of pretty. But! I've read that it is invasive. It is starting to climb the bricks of my house...

Should I leave it? If I do leave it, should I let it climb the bricks??

Much thanks.

Adrian Higgins: Virginia creeper is quite manageable. It may need cutting back once or twice a year but won't become a monster unless you let it. I find it one of the prettiest of all vines, especially at this time of year.

_______________________

Arlington, Va.: Greetings.

About when do you suggest for the last mow of the season? After the first freeze or sooner? Also, do you have any familiarity or recommendations regarding cordless electric mowers? Thanks.

Adrian Higgins: I use the mower to pick up leaves, so I am mowing away into December. Cordless mowers have a very limited charge and would be fine for a small townhouse patch of turf but probably not good for anything more than a few hundred square feet. You can buy a secondary battery pack. It's important to find a mower than will cut at three inches. I suspect too that in the spring, when it is wet and the grass is growing like mad, you will find that cordless mowers soon peter out.

_______________________

Greenbelt, Md.: I have some dusty millers that are beginning to look unkept. Are these annuals in this area? I would like to rip them out in order to have space to plant more bulbs.

Adrian Higgins: This is an annual and best removed now for tidyness and to make room for bulbs.

_______________________

Logan Circle, Washington, D.C.: Adrian, hello. I have fallen for the old rose alba semi-plena, which I understand can take part shade. However, this summer (its first in my garden) it barely grew, though it got four hours a day of sun. do you have any tips for making such a rose happy here in dc? Is its reputation for needing less sun overstated?

Adrian Higgins: Some roses will grow in light shade, I know the hybrid tea Gruss an Aachen takes some shade, but generally roses need at least six hours of full sun. This year seemed particularly cloudy, which is why your rose limped along. Don't expect great things from roses in shady sites. You might consider removing the lower branches of surrounding trees and shrubs. YOu can also paint walls and fences a light color, which will bring more light in to a dark area.

_______________________

Woodbridge, Va.: Adrian...happy autumn to you!

We're having a 10' crepemyrtle planted tomorrow and there's a fair bit of "deturfed" ground around the spot marked for the planting. What would you recommend for complementary vegetation to use around the crepemyrtle? I'm partial to hosta, but fear they would spread too well for the tree to thrive.

Thanks for the help!

Adrian Higgins: Greetings. I would keep plantings very simple and sober underneath a crape myrtle. Hostas would require more water than the crape myrtle might like. I would go with something like liriope, sweet box or pachysandra.

_______________________

Clarksburg, Md.: Adrian, thanks for taking questions and helping us out.

I've got a 12' redbud tree in the front that leans pretty drastically, 30 degrees or so. Will it straighten as it grows, or do I need to cut it down and start anew. I'm particularly worried as it leans towards the house, and while its not endangering anything now, I worry about 10 years down the road.

Many thanks!

Adrian Higgins: Why is it leaning? If it is reaching for shade, no amount of straightening could be expected. If that is the natural growth of the tree, you might be able to remove some of the secondary branches to encourage a more symmetric habit. This is another example of why formative pruning of trees is so important, to anticipate bad growth habit and fix it when young.

_______________________

Glenmont, Md.: My entire backyard is covered in trees, mainly oak. Is there anything else that will grow and hopefully flower considering the dense shade?

Adrian Higgins: Here's the trade off. Lots of trees create a beautiful, mysterious space that is cool in summer, but you have to let go of the need for flowers. In deep shade, you are better off finding color and ornament in leaf ornament, which such things as ferns, dead nettles, liriope, and epidimediums. Most wooded lots would benefit from a judicious thinning of the trees.

_______________________

Herndon, Va.: Thanks for taking my question! I have completely ignored my roses this year, no pruning, no feeding, nothing. What, and when, should I do to prepare them for winter and next spring, and to redeem myself?

Adrian Higgins: I would give them a feeding of organic fertilizer to restore nutrients and trace elements for the roots. Cut out any diseased or damaged canes, but leave the main pruning for late winter.

_______________________

Rockville, Md.: Hi Adrian,
We planted a fig tree last year and this year is is producing some figs. Just as the figs are getting ripe, they are stolen by, I suspect, squirrels. Last week, I tied some netting around a couple of fruits (the netting was from a bag that held onions). A few days later I found that the bag torn and the figs taken.

Any ideas on how to keep rodentia away from the figs? Thanks.

Adrian Higgins: Those squirrels have got a lot to answer for. Figs don't continue to ripen after picking, so you have to try some other form of barrier. Perhaps netting the whole bush.

_______________________

For Annandale, Va...: It could also be (eek!) a rat. Take care of that problem now!

Adrian Higgins: I was trying to avoid the R word, but it is quite possible, though rats are gregarious and likely to be seen.

_______________________

Rockville, Md.: What are the "wooly bears"? That's what I've always called them, anyway -- big fat caterpillars that are black on one end and dark orange/rust on the other... I'm enjoying seeing them, but should I be squashing them? Do they grow into beautiful butterflies or monstrous pests?

Thanks!

Adrian Higgins: They grow into a nondescript moth, probably with nefarious ambitions. If you see them wearing a muffler, it's going to be a lousy winter. If you see tiny sunglasses, we should be all right.

_______________________

Ashton, Md.: I have a Viburnum Carlesii (Korean Spice) that I planted eight years ago in pretty severely clay-bound soil.
Although I had dug a fairly wide and deep hole and amended the soil with leaf mold, the bush has grown to only about 4 feet tall and seems to have topped out. It is still healthy and produces wonderfully fragrant blooms in the early spring, BUT... is this all the larger it is going to get?

Adrian Higgins: They don't grow terribly high, but you may have a variety named Compacta, which only gets to about four feet.

_______________________

Arlington, Va.: I have a clematis growing in a pot on my patio next to a trellis. It did well over the summer. Is there anything I can do to protect it from cold weather/frost over the winter? Thanks for your help!

Adrian Higgins: I would not keep it above ground in the winter. I would sink the pot into the ground and give the roots a mulch of compost, but not shredded bark or other wood product mulch.
Lift the pot in March. Eventually, its roots will outgrow the container. Clematis are better suited to planting in soil.

_______________________

Silver Spring, Md.: Will be out of town so am submitting this early. I just moved into my first home with a beautifully landscaped yard. I have wonderful, large hydrangea plants whose blooms are all brown, but I noticed the blooms on my neighbor's hydrangea are a brilliant blue. Is there anything I can do to bring color back to my hydrangea?

Adrian Higgins: I think your neighbor's maybe newly purchased and greenhouse grown. Most hydrangeas now have the dried panicles, which are beautiful fall ornament. (I love the way the panicles of the P.G. hydrangea go from cream to rose for the fall).

_______________________

Lorton, Va.: Hi, Adrian,
We've just moved into a new house and have limited landscaping. I'd like to add some trees and take advantage of the end-of-season sales at many nurseries. Are there any special precautions I should take when setting in new landscape shrubs and trees in late October/early November?
Thanks.

Adrian Higgins: Good question. There are standard planting procedures that should be followed at any time of year, namely, that the roots are scored or otherwise teased from their potbound condition. Avoid plants that have a girdling root, i.e. one that is wrapping the trunk and destined to throttle itself. Typically the trunk base, the flare or crown, is set about an inch or two above grade. The hole is backfilled with a mixture of soil and mulch, and you give the tree a good soaking when at planting time and probably no more, unless November is terribly dry. Do remember to water it occasionally and deeply next spring and summer, but do not overwater, a common error.

_______________________

Silver Spring, Md.: My front yard has a 50 year old red Japanese maple tree. Over this past year, I have noticed several small dead branches and most notably cracks in the bark. Some of the cracks are quite large where the bark appears to be splitting. Do you know what is causing this? Should I be concerned or is this normal for a 50 year old tree? Maybe it's time for a new one? I appreciate any advise you can provide.

Adrian Higgins: Cracks are not good, and suggest a weak point brought on by poor plant architecture. Two equal trunks coming together at one point is a common source of this. I would not be quick to remove such an old tree, and perhaps you can thin it without butchering it. However, it may be old and reaching the end of its time, in which case don't feel guilty about removing it.

_______________________

Washington, D.C.: Rosemary, thyme, sage - will these winter over well in a protected garden if I plant them from 2" pots this weekend? How about any other herbs that might do well?

Adrian Higgins: It would have been better to have planted them in the spring, so that they would have become established at this point. Young plants are inherently more tender. Make sure you plant them in moist but well drained soil. You might also consider keeping plastic pots to place over the herbs on the coldest nights this winter.

_______________________

Silver Spring, Md.: Help! My rhododendrum did not bloom this year. It bloomed the year I planted it (last year). It seems healthy, but it is in a shady spot. Suggestions?

Adrian Higgins: It should have flowered, even in shade. If you pruned the fading flowers you may have removed the flowering buds for the next year.

_______________________

Vienna, Va.: After a year of effort, we seem to finally be winning in getting rid of the ivy and periwinkle the PO planted at the side of the yard. Now we have a large shaded area covered with black plastic. We are thinking of just covering the area with landscape cloth and wood chips. Is there anything you would suggest?

Adrian Higgins: I do not get poetic impulses passing a bed of landscape cloth and wood chips. I would rather see plants. There are loads of ground covers to choose from. Check out some of the books by Timber Press, some of which are dedicated solely to ground covers.

_______________________

Fairfax, Va.: I have a lot of perennials that are now looking straggly and untidy. How do I know when it's time to cut them back and do a major fall clean-up? And what about ornamental grasses? They look great, but should I let them stay over the winter or cut them back this fall?

Adrian Higgins: The garden should be put to bed for the winter. Perennials and annuals should have their dying top growth removed to make way for new growth in the spring. Nothing drives me up the wall more than seeing sedums, chrysanthemums or other perennials in spring growing through the previous year's dead growth. Also, it is psychologically important that the garden is clean and presentable going in to the winter.
Also, removing the material will reduce the chances of harboring diseases and pest.

_______________________

Laurel, Md.: I bought a beautiful peace lily about a year ago, but it has bloomed a flower in 6 months. I thought it was stressed. I repotted it only last week. I have been feeding it super bloom food once every two weeks, still nothing. It is still a lovely lush green plant, but no lillies. Any ideas?

Adrian Higgins: Stop feeding, start starving.

_______________________

Silver Spring, Md.: I have a slope in our front yard - I want to plant ground cover in since it is very difficult to mow. The front gets full sun - not really interested in ivy or pachasandra (sp) but rather something that remains green all year. Maybe something from a pine family that will spread - with needles??

Adrian Higgins: Pines are inherently architectural and given to specimen use. Even a low grower like a mugo pine would be ill suited to covering a hillside. If you want something evergreen, I would consider some of the dwarf varieties of nandina, as well as some of the prostrate junipers such as Juniperus conferta.

_______________________

Anonymous: Flowering myrtle?: I grew up with this ground cover in Ohio, but can't find it here in Virginia. It's wonderful stuff: easy to manage, doesn't climb, runners stay inside brick barriers.

Why can't I get it here? I seriously considering an 8-hour each-way road trip to raid an old friend's house back in Columbus.

Adrian Higgins: This is an old fashioned name for hardy periwinkle, Vinca minor. If this is what you are seeking, you will find it readily, no need to head west.

_______________________

Norfolk, Va.: Is the big light in the parking lot next to my garden, the one that stays on all night, the reason that my fall lettuce bolted in perfectly nice cool weather?

Adrian Higgins: Possibly, but more likely that it got uneven watering. Try again, but give it rich, evenly moist soil. The light will affect plants that need a certain amount of darkness to bloom on schedule, including chrysanthemums.

_______________________

Baltimore, Md.: We have a very old flowering cherry that may have been planted when the house was build 80 years ago. It has not received much care and has many "Water branches" that often die after they sprout. Schould we trim thes branches all at once or will that be too much of a shock to the tree? Every branch as many of these.

Adrian Higgins: Unless they are of great girth, I would try and remove all of them this winter, when the tree is in dormancy. Then keep on top of them.
Folks, we are out of time. You will see me back here after the winter. Enjoy the dark season and the idea that come Dec. 21, the days will be growing longer again.

_______________________