Adrian Higgins gives advice on grooming your garden

Nov 03, 2011

Learn about dry shade gardens, the best bulbs to plant for spring and other gardening advice.

Is it too late in the DC area to divide and plant hostas? Also, is it too late to plant tulip bulbs?

We're finally here, lots of technical problems with the website, but it seems to be working. Now is still a good time to divide and plant hostas, like many perennials, the top growth has pretty much done its work for the year,a nd the plant now wants to send out fresh roots. So don't worry about mangling the leaves, but do take care not to damage the crown and the latent buds for next year's growth. Tulips can be planted until the ground freezes, usually in late December.

We will be moving in the coming months (not sure when exactly), and I'd like to take the peonies with us, as they belonged to my grandmother's aunt. Am I better off digging them up now and storing them (how/where?) or should I wait and possibly need to dig them up in the dead of winter? Once we are at the new house, do I plant them right away, or should I wait til spring?

Dig them up now because the ground may be rock hard when you need to move. I would put the peony divisions in large plastic pots. Store them in a cool place out of the sun. When you plant them in your new garden, make sure the crown is buried one to two inches below the soil surface.

My home backs to a wood lot and deer graze in my backyard regularly. Can you recommend any dry shade plants that deer won't eat? Thanks.

Ajuga, liriope and pachysandra will all take dry shade and are somewhat deer resistant. No plant is totally safe, it depends on the number of deer and the severity of the winter. If you could exclude the deer with netting or fencing, your garden choices would be so much greater. Fortunately I don't live in deer territory, but if I did, the first thing I would do is seek to exclude them.

What small evergreens could I try In my shady, dry, narrow side yard bounded by a concrete wall and a sidewalk? I have had good success with siberian iris, ferns, lilly of the valley, but in winter I'm left with just hellebores and some big empty spots. I have thought of skimmias but what else might give us some winter presence? Thanks.

A lot of evergreens for shade dislike dry soil, they have evolved in woodlands where the leaf mold is deep and retains moisture. I would consider Chinese or yaupon hollies (they can take dry once established) as well as yew. I have grown osmanthus in dry shade, and they do grow happily once they have developed a decent root system. Mahonias will flourish also, as will aucubas.

Adrian, I AM SO HAPPY YOU ARE CHATTING! (I really HATE that they took you off the regular chat lineup, BTW.) At any rate, question is this: Is it okay to rake leaves into perennial flower beds, borders, etc. as cover during the winter? Or is this just being too lazy?

Great to be here. I am a big advocate of not bagging leaves and leaving them for the landfill, what a waste of garden treasure. But they do need to be shredded somewhat before being returned to garden beds. If you can go to the bother of mowing them and then raking them into your perennial beds, they will break down quickly without smothering plant crowns.

Thanks for your article on dry shade. I suppose the book you discussed also lists some ferns that do well in dry shade. Christmas fern and southern shield fern are two that can take some sun and dry shade here in AL.

Thanks. The book is called Planting the Dry Shade Garden by Graham Rice. He spends a lot of time on dryopteris varieties, so those ferns must work for him. 

I have been composting food scraps, lawn clippings and fall leaves for about a year now, and finally have something worth spreading. Should I mix this into my garden soils now, in the fall or wait until sping? Thanks!

Now is a perfect time to top dress garden beds with finished compost. This will smother emerging weed seeds (believe me, they are about to explode) and give the earthworms something to do over the winter. They'll pull the black gold down into the soil and all the microbes will be happy for the holidays.

Hi, Adrian. Enjoyed the article today. I have a back yard garden shaded by 10 or so mature tulip poplars (.3 acre lot). How do I know what to have pruned to let in a bit more light? Is it on a branch by branch basis, or pruned up to a certain point?

Tulip trees tend to be marvelous because they self clean lower limbs and provide the sort of high, dappled shade that many shade plants love. If they are crowded, you may want to get an arborist to look at them and see if the weaker ones should be removed.

I have several shrubs (salix integra, yellow-twig dogwood, Korean lilac) that need to be pruned. Is now the right time to do it? (I live on the upper Eastern Shore.)

The best time to prune all of those is right after flowering in March and April. The willow and redtwig dogwood's color is most pronounced on young stems, so I'd just remove the oldest canes and let some new ones grow. Remove the lilac blooms as they begin to fade.

Hi, Adrian. The weather here in Northern New Jersey is unseasonably warm. It reaches the low 30s at night but daytime temps are reaching 60 and beyond. My question is: Should I cut down perennials like hostas, ferns, catmint and epimedium now, or wait until it gets consistently cold and they fade more? Everything is still pretty green. Thank you.

I would keep them as long as they look attractive. I also like the way the frost rimes them at this time of year. I like to keep my epimedium foliage until late winter, because it still looks good, and then remove it before the flowers shoot up in early spring. If you want to tidy things up, I would start with the hostas and move to the catmint.

Adrian, I just moved into a townhouse that has areas I am able to plant in the front and back. Everything was covered in weeds, which I have now pulled. I plan to put some tulip and daffodil bulbs in this weekend (it didn't really freeze, so I'm hoping that's okay) and another area I am going to use as an herb/vegetable plot. However, I'm left with a strip of earth about 2' x 6' and two strips of earth that are about 3' x 5'. Can you suggest something I can plant now that would fill these areas in? I'm not looking for ground cover, but rather some short (preferably flowering) bushes or plants that will look nice after their flowering period is over.

I am a huge fan of a deutzia called Nikko. Plant a massing of those.

Such great timing! I just closed on a new home that comes with large built-in planters on the patio (and a few potted plants as well). Having always been an apt-dweller with no outdoor space, my "gardening" is limited to a bonzai and a few ferns I've managed to keep alive. But I'm excited for this potential. My question: Any special steps I should take to help the plants in the planters survive the fall, frost and winter? There's bamboo and a few other stalk/leafy (seemingly hardy) plants, but I'm a total novice. Would trimming them back this late in the season do any harm? (It's become a bit overgrown in the months we were under contract.) Will they survive any D.C. snow and cold on their own, or would covering with mulch help? The potted plants will be indoors before the first frost.

Without knowing the type of bonsai, it's hard to say whether it would be hardy or not. As a general rule, plants in pots have to be hardier than those in the ground because the soil temps are so much colder. If you think them hardy, I would just make sure the pots are watered well and that they drain, and perhaps drag them to a sheltered corner. I would wait to prune until late winter.

We have one spot in our yard that has poison ivy. We keep pulling it, we put a raised bed on top of the place where it had been, but our neighbors don't control it in their yard, so it keeps coming over into ours. We have a toddler and a dog, so we'd rather use non-toxis means to rid ourselves of it, but really want to be rid of it. Any hope for us?

Roundup is highly effective before the leaves drop. You can apply with a paint brush to target the vine. Otherwise, it's a case of being vigilant (and protected) while pulling or treating the plant as it grows during the spring and summer.

Thanks for chatting! My roses, Knockouts and others, are still budding and blooming. I think I'm supposed to be cutting them back extremely and protecting them with a few inches of mulch for the winter, which can get pretty cold in southcentral Pennsylvania. But I can't bear to whack them while they're still flowering! Can you please tell me how late in the winter I can safely prune them? Thanks so much!

I think you are still far enough south not to go to extreme measures to protect your roses for the winter. If you don't want to risk it, you could pile leaves or pine needles  in the crowns for December to March. Knockout was bred in Wisconsin, so winter protection isn't necessary. Don't do any pruning now, you may encourage new growth that will be damaged.

I live in New Hampshire and the October snow storm crushed my lilacs.  I have broken branches everywhere. Do I just cut below the broken area and hope for the best next spring? Is there anything else I should be doing to make sure they come back strong after losing at least half of the branches?

Make clean cuts where the broken branch meets an unbroken branch. Take the opportunity to remove some of the oldest stems to promote general rejuvenation. Blooming will be off next spring, but will come back with a vengeance the following year.

Thanks for already answering the question about dividing hostas. This Sunday I will be dividing by beloved Hosta "June". I living in a row house in B'More with a giant London Plane tree in the backyard. June is planted between two roots and is badly overdue for dividing. Any special tips? Also, I think I need to divide my Helleborus Orientalis, too. I've never done that. Anything I need to look out for? Thanks for today's chat, Adrian. I miss your regularly weekly chats.

Don't divide the hellebore, it doesn't need it or like it. As for the hostas, lift the whole clump and then separate it, taking care to keep divisions with bud eyes and roots. Discard the old, woody centers. If something is really mud bound, I take a hose and wash off all the soil before dividing it. I also like to soak the divisions in a 5 percent bleach solution to kill pests. 

We put in a new planting bed a year and a half ago where a yew hedge used to be. It gets a bit of sun for a few hours a day, but is under high shade of big oaks. We have already lost three or four lamiums (dead nettles, for real!), one of two heucheras, and a rhododendron suddenly started declining (whole branches of leaves curled up and turned brown) this August. Our basic soil is clay, but garden center installed the plants with lots of topsoil, and we keep light bark mulch on it. What to try?

I'm wondering if you are overwatering this area. Also, many rhododendron varieties don't fare well in our hot climate, you do have to pick varieties that work here.

We bought a house with mature gardens that include fall mums, plus some that I bought last year came back, so I planted them as well. I pinched them all up until July 4 or so and the ones that came with the house bloomed in October. The others are just now about to bloom and I am afraid the cold might get to them before they totally open up. Should I not have pinched them? Thanks!

You should pinch them, that will promote bushier growth and better flowering. It won't really delay the flowering, many varieties naturally bloom late and can take a few frosts. Mums that are purchased in September and early October are often forced and that is not their natural bloom season.

With the first few frosty nights, our front lawn starts resembling a field of straw. Many years ago we tried removing the top layer and replanting with bluegrass seed, but it was overtaken by the stray roots of zoysia again. Any suggestions for a solution for our half acre front yard? ( It would have to be done by someone else, since we are past the lawn-renovation expiration age.)

Zoysia spreads by runners and will take over cool season lawns unless there is some barrier to stop it. Bluegrass is not the best cool season variety for the DC area, it's just too high maintenance for most people. The best grass is turftype tall fescue and it's best to select a variety that has been bred for southern climates. The Rebel family is a classic strain for hot climates. However, it's too late now to seed. (You could try and then re-seed in March). The optimum period for seeding is mid-August to early October.

I live in New York city and occasionally, though not typically, my rosemary can survive the winter outside. I was thinking of bringing it in this year, but my apartment doesn't get much light. Am I better off leaving it in the cold where it can get more sun, or bring it inside where it's warm but not sunny?

You are better off leaving it outside, perhaps with some sort of covering on the coldest of nights. The best way to get rosemary through a cold winter is to provide it with excellent drainage and to select a variety that is cold hardy, such as Hill Hardy or Arp. Rosemary plants hate being inside dry, dark rooms and will soon die in that environment.

As you mentioned, potted plants need to be heartier because they are more exposed and get colder. Is there a way to insulate potted plants for the winter to keep them warm? What would happen if I wrapped the pots with insulation? Or if I buried the pots in the ground for the winter. Would this help keep them warm?

I'm a fan of burying pots in garden beds and then covering them with leaves or something. Recognize they may freeze in place and be unmovable until the ground thaws but if the pot itself is freezeproof, that's not a problem.

Adrian, based off your answer to the question re: top-dressing the garden now with compost, does it matter if some food scraps are still noticeable as food scraps? Also, since I have lots of earthworms in my compost, I'm assuming putting all of this onto my garden and other beds is preferable, so they can get into the soil before it (and they) freeze in the compost? Or is it okay to keep them wintered over in the compost heap? Thanks!

I think your compost needs more time to finish, do this by adding shredded leaves to the pile, turn it a bit, and use the compost in the spring. The worms in compost are different to the worms in the soil.  Don't worry about the worms.

I have been sporadically cutting the vines that are killing the trees in the wooded area near my house (I think the property belongs to the county) and was wondering if this is futile. The trees are better off of course. But am I approaching this the right way?

I think this has to be the last question. Large vines on trees are harmful but can be defeated by cutting them close to ground level to separate them from their roots.  They will take a while to die and then may take two or three years for storms to remove the dead vines from the trees, but they will. Thanks for all your questions and hope to see you here again soon. Enjoy the fall while planning for spring.

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Adrian Higgins
Adrian Higgins is The Washington Post's gardening columnist. Read his latest story on dry shade gardens and more of his columns here.
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