Repairing winter damage

Adrian Higgins
Washington Post Gardening Columnist
Thursday, March 18, 2010; 12:00 PM

Washington Post gardening columnist Adrian Higgins was online Thursday, March 18, at Noon EDT to discuss how to repair winter damage in the garden for a perfect spring.


Adrian Higgins: Hi everyone. I'm ready for spring this year, so let's get down to it.


Richmond, Va.: My new neighbors just butchered their crepe myrtles: lopping off the top 24 inches of delicate branches and leaving stout stems. I was hoping the general public knew not to do that any more.

Adrian Higgins: I think you should only get a crape myrtle with a permit showing that you have completed a course in crape myrtles. The practice of topping crape myrtles, long practiced and often aped, will only encourage rank growth of suckers. It mutilates an otherwise beautiful plant. If your crape myrtle is too big, you picked the wrong variety.


Baltimore: Several of my Thuja trees about 8 feet tall got bent by the heavy snow. The snow is gone, but the trees are still seriously bent over. Should I stake them upright or will they come back to vertical in time?

Adrian Higgins: We cover this topic in our package today. If the tree is young and if the tilt is not beyond, say 45 degrees max, you can upright it. You will need to run a deep stake into the ground and then put a guy wire to the tree, using garden hose or some such, to stop the wire from cutting into the bark.


Capitol Hill, D.C.: The snow killed one of my azalea bushes. It's not a disaster because I've often thought I'd prefer a tree peony in that spot. Can I plant a tree peony at this time of year?

Adrian Higgins: Yes, you can. Tree peonies have just broken bud and are about to bloom, but if you can get one now and handle it carefully, there's no reason why you can't plant it.


Columbia, Md.: Thank you for this very timely topic. A large branch on flowering crab tree broke partially off in one of the heavy snows. It was hanging on by a strip of wood and I had to saw it off so my neighbor could get out to her car, leaving a long barkless strip where the branch pulled off and also the stump. What can I do to protect this and keep this lovely tree? Thanks.

Adrian Higgins: I'm not sure of the extent of the damage, but stripped bark is not good to keep, unless you have to in order to preserve the tree. In our package today, including the video online, we show how to cut a branch in a way that avoids tearing the bark.


Baltimore, Md.: I have a row of hollies which were decimated from the storm. The problem wasn't the falling snow. Instead, it was the plow piling the snow on top of the hollies. Truly there was nowhere else to put it.

This year was particularly bad, but we have had this problem before. I would like to replace the hollies with some sort of bush-like perennial that could be cut down each year, but would grow enough to block the view of the driveway (4-5 feet high would be ideal). Area gets morning sun, but is in the shade most of the day. Any ideas? Thanks

Adrian Higgins: I would consider an upright ornamental grass, such as panicum or calamagrostis, that will give you ornament and screening from June to December.


Arlington, Va.: A friend of mine is selling her home and has kindly offered me a few perennials. I am a veggie community gardener and know very little about flowers and shrubs. Among the gifts are iris, hosta, day lily, and American Beautyberry. She dug them last night, so I know I need to get them into the ground this weekend. Are these all full-sun items? Can any take partial shade? Can any of these tolerate high-moisture areas? Do I just dig a hole and plunk them in, or do they need fancy enriched soil and/or fertilizer? Thanks much!

Adrian Higgins: The only one that will take a lot of moisture is the hosta, which also takes the most shade. The rest would prefer a sunny site and reasonably good drainage. The beautyberry is a shrub, but you can treat it as a perennial, cutting it back now to just a few inches above the crown.


Alexandria, Va.: Hello! How far back can overgrown rhododendrons be cut back without stressing the plant too much? I've cut back about a third with success, have a large old one that really needs much more than that.


Adrian Higgins: I would probably wait until after blooming in May and then cut it back to keep its layered shape. You don't want to remove more than a quarter of the shrub per annum.


Washington, D.C.: Is it too early to cut back roses? Thanks!

Adrian Higgins: Bush roses should be cut back now. They have broken into growth, but treat the shoots as buds, i.e. cut to just above an outward growing bud. Remove dead and diseased canes, and canes that are growing inward toward the center of the plant.


Silver Spring, Md: Not a snow question, but is it acceptable to divide day lillies now, as they've just popped up? What about daffodils that have budded but not bloomed yet?

Adrian Higgins: You can divide daylilies now, I wash the mud away with water and then pull them apart with my hands. Soak them in a bleach solution for a couple of hours before replanting to kill thrips and stuff. Daffodils can be moved if you must but they'll bloom in a couple of weeks. But if you must, lift them with great care and replant them immediately, preferably on a cloudy day.


Hope: My dwarf nandina lost about a third of its top when snow built up on it. Given the leafy nature of the plant, I'm intending just to prune away the broken wood and see what it does over the summer before making a decision about replacement. It seems to me that this would be a good idea for hollies and other plants that look bad right now but may put out lots of new growth in the coming couple of months. Unless they were topiaries...

Adrian Higgins: Nandina will rejuvenate willingly, and you can either cut back to reduce in height or cut it to the ground, where it will sucker. However, if you remove the canopy of dwarf varieties, you'll be looking at a hole for year or two.


Germantown, Md.: I meant to ask you this last summer and forgot, so here it is - last year by the end of August, 90 percent of the cherry trees in my neighborhood (we have quite a few) had lost 90 percent of their leaves. They appear to be producing buds this year but I wondered what caused the early foliage loss. Last summer was pretty unremarkable as far as weather went.

Adrian Higgins: We had a lot of rain early in the season that induced a lot of leaf spot disease. Cleaning up last year's leaves is going to be really important now before the plants refoliate, to remove a source of fungal spores. Not just for cherries, but all sorts of deciduous shrubs and trees.


Richmond, Va.: Mr. Higgins (my favorite Post-er!!), would you mind giving me a little advice?

I have some type of wire grass in my yard; I'm not sure what kind it is, but it is definitely tenacious. I don't want to kill this grass outright with an herbicide, but I would like to diminish its hardiness and work in another type of turf to replace it. How would I do this? Are there selective herbicides or a regimen I could use to curb its enthusiasm which can be used at the same time I am promoting/planting a new turf? It covers a large area, so I am also loathe to dig it out.

Adrian Higgins: Aww, thanks. This is what Scott Aker in our now former Digging In column had to say about wiregrass or Bermuda grass. Richmond is right on the edge in terms of cool and warm season turf grass varieties.

Q: I have a constant battle with wire grass. Each year I tear it out, but by season's end it has overtaken my flower gardens.

I don't want to use herbicides around my gardens. Can you recommend a reasonable control? A: The key to managing wire grass, more properly known as Bermuda grass, is getting rid of it entirely. If the turf bordering your landscape beds and flower gardens has been infested, the weed will inevitably creep into your beds. If you can't kill the entire lawn, you can arm yourself with a sharp straight-edged spade. Use it to edge your beds every year throughout the summer to remove any invading rhizomes before they have a chance to become established.

You can use a selective grass herbicide such as Grass-B-Gon to kill Bermuda grass in beds containing ornamental plants. The best time to spray the grass is late summer. Check the label to see if it can be applied safely to the plants you are growing in your garden. If you don't want to use chemicals, you will have to resort to careful digging to remove all traces of the rhizomes.


Stockton, N.J.: Hello Adrian, how do I get rid of moss and keep it away around my garden? I am encouraging it in certain areas of my property, but it's spreading where I don't want it. Thank you!

Adrian Higgins: There are chemicals to kill moss, but that's treating the symptom, not the cause. Moss grows in compacted soil that is acidic and poorly drained, and does best in the shade. If you can correct those elements, you'll solve the moss problem. If you think it a problem. Some people cultivate beautiful moss gardens, which are a lot of work.


Anonymous: How do you prune forsythia bushes that have been damaged by the winter storms? Mine have rather long branches which are now lying on the ground after the weight of the snow. How far back can I prune them? Is it okay to prune them even though they have started to bud?

Adrian Higgins: Are you anonymous because you have a forsythia? No need to be. You should cut away entire canes to the crown, usually one third per year so that the plant is totally rejuvenated after three years. This is normally done right after flowering. I would wait to see if your flattened stems spring up as it blooms now. Or, I would cut them and bring them indoors to enjoy.


Bristow, Va.: Please provide the one veggie you would plant, for the largest dividend returned. I feel you will say tomato!

Adrian Higgins: I couldn't live with one veggie, but if I had limited space and time, I would sprinkle a mesclun mix. You harvest the baby greens as a way of thinning them, and then you cut the maturing leaves with a scissors to allow regrowth. It will give you salads until the heat causes the greens to bolt.


Growing fruit and herbs in VA: We're in a temp rental, but I still want to grow some tomatoes, herbs, peppers, etc. Can I put the tomatoes and peppers in a pot instead of planting them in the ground? The soil here isn't that great. Also, the backyard is mostly shaded with some areas of diffused sun, so will this even work? And lastly, is it too late to start from seeds if I do it this weekend? The herbs I'm fine with - mostly basil, chives, oregano... but I will be using the mostly shaded yard if it's possible.


Adrian Higgins: You can successfully grow tomatoes in large containers (look for determinate varieties) but not in shade. Basil can be started from seed indoors and go out in early May when it warms. The other herbs are hardy, semi-woody plants that can be raised from seed, but will take two or three years before they reach harvestable size. Herbs generally need lots of sun and free draining soil.


Courtyard tree: I live in a garden condo community, and we lost our centerpiece courtyard tree (a small ornamental cherry) to snow damage. The courtyard gets full sun, and the four surrounding buildings are three stories. Any suggestions on a replacement tree?

Adrian Higgins: I would suggest perhaps an Okame cherry or a Japanese apricot.


Arlington, Va.: Hi Adrian, so good to see you back in action again. I am planning on installing some potted herbs in a sunny spot in my kitchen (cilantro, parsley, chives, and one other as yet undecided but won't be basil). I was planning to get these from a garden center in the area rather than starting from seed. Can you offer any tips? Thank you!

Adrian Higgins: They wheel me out now and again. If you are growing these indoors, they will do fine as long as they get enough light. That is quite a proviso. They would be much happier outdoors in the sunlight. Cilantro is a cool season annual that you could buy now and it will be good until Memorial Day with some attentive watering. I have some seed started that will be going out in a couple of weeks.


Crape myrtles: I recently bought a house and it has a crape myrtle in the back yard (no idea what kind). I'm fairly new to gardening so how do I know if the previous owners butchered it, as referred to in the beginning of the chat?

Adrian Higgins: Crape myrtles should be pruned (best when young) in a way that doesn't look as if they have been pruned. By removing entire branches, you open up the plant, make it less prone to storm damage, and expose its primary ornament, which is not the flower, but the bark. If it is arbitrarily chopped, it looks ugly and will suffer from rank growth. We did an online graphic on correct pruning of crape myrtles that's in our archives.


Anonymous: Thank you! I am no longer ashamed of my forsythia.

Adrian Higgins: Oh good.


Alexandria, Va.: RE: Growing fruit and herbs in VA - Just look at EarthBox, or the Gardener's Supply catalog or any similar retailer. There are a multitude of container systems out there now designed for growing herbs and veggies on the patio. Many are self-watering and practically trouble-free. I planted hot peppers in an EarthBox last year and they got about 5 feet high and exploded with peppers all the way through November.

Adrian Higgins: Yes, but they are expensive and a lot actually aren't as effective as billed. Sometimes the self watering features don't work adequately, in my experience.


Washington, D.C.: On a neighbor's recommendation, we cut back our liriope in the fall and it seems slow to come back (no new growth yet). Is this normal or did we hurt the plants?

Adrian Higgins: I would cut it back now (or a month ago in a normal year) because the old growth provides some cold protection. The new growth will erupt next month.


Bethesda, Md.: I saw the description of how to repair a splayed evergreen on p. 7 of the Home Section. I assumed this applies to Arborvitae and the like; but can I also try it on a rhododendron? It was about 3 ft high and wide; now it's a bit wider, so could I gently pull the outer branches together, say, just a couple inches this week, and maybe a couple more in 2 more weeks? Would it better to try slowly and gently staking a few of the worst branches? Or should I just lop off those that are now basically parallel to and a foot off the ground? (It's not in the best of health, and only has about 6 or so branches anyway, so I hesitate to cut anything.) Thank you.

Adrian Higgins: No, that was more geared toward upright conifers. I would wait a while to see what springs back and if it doesn't, conservatively trim away the outermost branches that are on the ground. I wouldn't stake a rhododendron.


DC: Two questions:

1. How worried do I need to be about poisonous plants and my kids? Specifically, I am wondering about hellebores. I keep reading that they are toxic, but is this toxic like if my two-year-old touches them she will keel over or toxic like if she ate several whole plants (unlikely), she would throw up?

2. Trees with roots running all over on top of the lawn. They make it really hard to mow. Can I bury these suckers under a load of topsoil/compost and plant on top, or are the roots exposed because the roots want to be exposed?

Adrian Higgins: I think with a two year old, you need to keep an eye on the little person to avoid any ingestions, including soil. Lots of plants are actually very poisonous if you eat them, and in enough quantity, but this rarely happens.


Baltimore, Md.: I have several azaleas and boxwoods(baby) that were destroyed during the snow. Do I have to wait until the ground completely dries out before removing?

Adrian Higgins: The ground is drying out quite well with this warmth. If you are leaving a footprint in it, it's still not good to work in it. Wet soil can have the oxygen and hence the life squeezed out of it. I would be worried, for instance, about crews of landscapers laying mulch in wet beds at the moment, for that reason.


Alexandria, Va.: My worst snow damage is a giant butterfly bush that looks like an elephant sat in the middle of it. Any suggestions? Prune the half that sticks out the most?

Adrian Higgins: That's one of the plants that will not mind the breakage. Just cut the stems back low to the ground, and it will spring back with a vengeance, and bloom merrily.


Japanese maple: I have a rather small Japanese maple--no higher than 3 feet. There are two breaks in secondary branches. I'd like to try the guidance in today's article to drill a small hole and bolt it; how can I best do this without further splitting the branches?

Adrian Higgins: This is a last resort effort to save a specimen plant. I would use a small nut and bolt but with washers on each end, and drill the hole first with a sharp drill bit, while someone else is holding the split together. If it is too fragile, it may all fall apart, of course. Mind fingers.


Annapolis, Md.: Good morning, favorite gardener!

I have so far discovered three sad issues in my garden: 1. A slightly delicate D. Austin rose, which is down to one healthy cane.

2. A formerly flourishing rosemary shrub, which is now half-dead.

3. A contorted fig (?, I think it's a fig, but it's certainly contorted), which was broken 6 inches off the ground. It also is in a spot that now appears to be poorly drained.

I guess the most critical is my sad contorted friend. Should I try to save him? Will new shoots also be contorted? Can I try to lift him up a little bit to solve the drainage issue? Please tell me he is not a $50 loss.

Adrian Higgins: Greetings.

David Austin roses, while beautiful and fragrant, can be hard to grow well in our climate. I would cut back the cane and begin a program of preventative fungal spraying. Give a top dressing of rotted compost. We are a seeing a lot of rosemary damage, perhaps more related to the cold before the snow than the snow itself, not to mention the wet conditions. Cut out the dead wood and see if the shrub regrows. It may not, I would have a backup ready to plug in there. Cut out the fig damage, but wait until you see new growth so you can see what if any top growth has been freeze killed. It will push new suckers from the roots, which may not fruit this year, but will eventually.


New Hope, Pa.: Adrian, we lost some beautiful, mature white pines in last week's storm. They provided cover between our property and our neighbor's driveway. What is a fast-growing evergreen we can purchase to fill the gaps left by the white pines? We have many deer in our area, so a deer-resistant variety is imperative.

Adrian Higgins: Here's the difficulty, the faster growing the screen, the more prone it is to future damage and breakage. I would try cryptomeria, or an upright conifer named incense cedar.


Falls Church, Va: Thank you for taking my question.

Please tell me how I can kill off my very invasive fountain grass. It is beautiful in small doses but when you have a dog that loves to brush up against it, and spread it all over the property it is a problem. Thank you.

Adrian Higgins: I would say you can lift them with a sturdy trowel. If that doesn't work, use a shovel. For deep rooted weeds like violets, I have been known to use a mattock. Alas, we have run out of time. The good news is that spring is just about here, and now is a great time to be out in the garden, cleaning up, but thinking about the uplifting qualities of the plant world. See you in the paper and online.


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