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Get gardening advice from Marjorie Harris

Got a gardening woe you could use some help with?

Whatever your dilemma - be it choosing the right plants, ridding your garden of pests or caring for a delicate plant properly - Marjorie Harris, author of the Globe's weekly Hurried Gardener column, can help.

Ms. Harris was online earlier today to take your questions.

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Marjorie Harris is considered one of Canada's leading garden writers. She writes a weekly gardening column for The Globe and Mail and is editor-at-large of Gardening Life magazine. Born in Shaunovon, Saskatchewan back in the mists of time, she was educated from Goose Bay Labrador to Vancouver B. C. and graduated from McMaster University.

She is the author of 13 gardening books, her most recent being How to Make a Garden, The 7 Essential Steps for the Canadian Gardener, published by Random House.

Editor's Note: globeandmail.com editors will read and allow or reject each question/comment. Comments/questions may be edited for length or clarity. HTML is not allowed. We will not publish questions/comments that include personal attacks on participants in these discussions, that make false or unsubstantiated allegations, that purport to quote people or reports where the purported quote or fact cannot be easily verified, or questions/comments that include vulgar language or libellous statements. Preference will be given to readers who submit questions/comments using their full name and home town, rather than a pseudonym.

Joan Armstrong, Park Conrer, PEI: Hello Ms. Harris, I am gardening under rather harsh conditions on the north shore of PEI. In the last three years I have managed to establish quite a number of plants in spite of significant winter damage and stinging assaults by wind and salt mainly in early fall. Just as things were beginning to look good with the new year's growth a storm blew out of the north west for two days (last Monday and Tuesday) with relentless wind gusting to 60 km/hr blowing a thick salt spray with it. I am saddened and discouraged by the damage, but I know that is what I must expect here. I've experienced this in September in previous years and didn't feel quite so upset since that is a time the garden is naturally winding down.

Although Zone 4 (some say Zone 5!) I have planted material tolerant to Zone 2 and 3 conditions for the most part, and have paid attention to salt tolerance so most things will likely survive in the end. My question is really what I should do to help the damaged plants recover and get through the summer months ahead. I 'washed' and watered those things that looked worst the day after the storm and now many other things are showing signs of burn. Attached are photos of the tips of the Anthony Waterer spirea I planted last Saturday, and a view of the worst hit plot that contains several rugosa roses (that have been great although showing some brown leaf edges now), a Gold Flame spirea that had just been showing nicely after coming back from winter, and some Karl Forester reed grass that is now in its fourth year, among other things. The Arctic Blue Willows, lilac and some of the daylilies have drooping and browned leaves. Should I remove the damaged parts of these plants? Concentrate on watering to dilute the salt that will be in the soil now?



Marjorie Harris: Dear Joan: You probably have sandy soil as well as salt spray and that means it's tough for the plants to absorb water. You'll have to really clean them off and water them slowly and deeply.

I'd cut off the damage parts very carefully but no later than this week or you'll be getting new growth that won't stand up to colder temps as we get closer to autumn.

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Consider having wattled wind breaks near your plants to help them withstand the spray; mulch deeply with organic matter so the salt water doesn't penetrate the soil (well not too much); Rugosa roses are your best bet; but also try Ilex verticillata; baryberry and sumach all shrubs that will tolerate salt spray.

A. Sumi, Vancouver: Is it okay to prune rhododendrons? If so, when is the ideal time to do this? I have one rhodo that is very leggy and am wondering if I cut it back severely, will it grow back? I am in Vancouver, zone 6, I believe.

Marjorie Harris: Vancouver is usually Z7, you lucky dog. Yes, prune the rhodo. Wait until it blooms in spring; deadhead (take off the dead blooms....look at my video on this site) and then prune for shape making sure you don't cut out too much. Get rid of dead looking stuff first and then for shape.

Terry Carter, Toronto: I have 2 or 3 kinds of lavender which looked lovely in bloom and are now looking scraggly. Should I cut them back? Or leave them (they still smell lovely when I rub them)? Any advice would be appreciated.

Marjorie Harris: Lavender should be cut back now while it's still got that wonderful scent (put it in pot pourri and keep it in your bedroom); just cut back to the wood stems. No more than that you don't want to encourage new growth this late in the season.

TJ, Canada: I have a very healthy looking, south- facing, pink hydrangea which didn't bloom at all this year-not one. What's the deal?

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Marjorie Harris: Many hydrangeas had a problem this year: January was so warm some almost broke bud, then got whacked back by cold weather which would explain no blooms. But if you've been cutting it back, you might have cut off all the buds. Many hydrangeas bloom on old wood. You should know the kind you have a research it carefully. Leave it alone for another season at least. If it doesn't bloom next year, cut back drastically and hope that something happens.

Mark McKeating, Hamilton, Ont.: Marjorie, about a month ago I had 3 emerald cedars planted. Two of them are now a golden colour. The other cedar is fine. I have been watering the two sickly ones overnight with a trickle of water. Should I give up? What do you suggest? Many thanks.

Marjorie Harris: Emerald cedars would be golden. Were you on a warranty? Did a nursery guarantee them? If so call them. And overnight trickle is probably way too much water. You need only do that for an hour or an hour and a half. You may be drowning your plants. Stop water the one remaining until it needs deep watering. Mulch it so it can get a good root system going. And call the nursery about the yellow ones.

Jim Sheppard, Mississauga, Ont.: I've planted Italian zucchini in my garden for the first time and they are growing like crazy. They seem to be medium-sized in general as they ripen, compared to the baseball-bat size that regular zucchini can hit. My question is: So, what's the best way to tell when they are ripe and ready to pick?

Marjorie Harris: Give them a gentle squeeze and you'll know if they are ripe. They may be a whole lot tastier than the baseball bat size. I'd experiment with one and see how it tastes. You can always spit it out.

Scott Thomas, Canada: Hi Marjorie, the city of Toronto bare-root planted four chanticleer pears on my boulevard, and true to the instructions left behind, I've been watering them deeply every day. The leaves are very droopy, there aren't a lot of them, and the ends of the new ones are black. I now think that I've been overwatering, and have held off for the last few days - the soil around the base of the trees under the mulch is still not yet dry. It's going to be 35C today, and I worry about holding off watering in this weather.

Marjorie Harris: If the soil under the mulch is wet, leave them alone. You might have been overwatering. This is a really tough call right now: we've had a drought and now we're in a heat wave but overwatering can also be a problem. Keep your eyes on the soil and the minute it's start to even vaguely look like drying out, water again but very deeply so that it's really wet under the mulch.

Jess Hungate, Toronto: Two questions, from Toronto - I have a small and heavily shaded back yard, and am looking for some nice flowering plants - the soil on top is OK, but underneath is heavy clay. And on the front, it's the same soil, but heavy sun/heat all afternoon (W facing with no shade) - there my question is, what about a good 'cover crop' for the relatively small area involved, which wouldn't require lots of water, and would provide an interesting green background into which some plants could be placed - to replace lawn which just doesn't do well in those conditions (we can't afford a full time gardener). Thanks!

Marjorie Harris: Back: add as much horticultural sand (it's not play box sand) as you can afford. Buy it by the bag from the nursery. Dump it all over the back to improve the texture of the clay beneath. Plants don't really flower in heavy shade but choose a selection of hostas in gold and cream and variegations. Ground covers such a lamium and pulmonaria have blooms in spring. And look for some annuals such as impatiens to get a little light tone. Do the same for the soil in front and get a collection of sempervivums (hens and chicks); sedums and other plants which have high water retentive qualitys (that is very fleshy leaves).

Ann Bishop, Regina: Hello, Marjorie. I have a question about raised beds. I have several raised perennial beds in my garden which suffer semi-serious attrition each year, I suspect from the roots freezing. The beds are well drained and well fed and are in partial shade. I live in Regina (zone 2b) and have quite severe winters. Can you suggest some hardy perennials (particularly fairly tall ones) that would do well? Thanks.

Marjorie Harris: The conditions you describe sound pretty good but to protect roots you'll have to have beds that are raised at least a foot. And if you have deep snow you will have wonderful protection.

Try the great prairie plants such as echinacea (coneflowers), liatris and some of the superb prairies grasses such as little bluestem. Veronicastrum is another native plant that will do well. Try a Rosa glauca (R. rubrifolia) and see if it works for you. Let me know about this. It's a great favourite of mine and it is supposed to be hardy to Z.3 and I'm betting it will be good in your circs.

Muthu Swami, Toronto: i have a flourishing flower garden because I use lots of homemade compost, I think. But the garden is blighted with earwigs which eat the leaves and flowers. I bought from Leevalley a few containers to trap them but they dont work well. I cannot see them in the day. I dont know where they hide. Can you please suggest something to destroy them? Have you tried Neem oil to get rid of pests? I cannot do hard work. I am 81 and arthritic. Please suggest something simple. Thanks Swami

Marjorie Harris: Neem oil was going to be the panacea of all gardeners but apparently not. It works well for somethings. Ear wigs are horrendous beasts and with all the heat this year they have not only multiplied hugely, they have munched their way all over the place. Put out a folded umbrella at night, leave empty rolls from paper towels out and about. First thing in the am dump the collected bugs into a bucket of water. Drop a bit of oil in there, watch them drown.

Michael Aston, Toronto: Something is eating away at and almost entirely killed off my marigolds - which I thought repelled certain bugs. Now they are going after my basil and certain hostas... What do I do?

Marjorie Harris:Depends on the bugs. Usually they are used to suppress nematode damage in the soil. But you sound like you might have earwigs so see the above advice.

Cecilia Li, Toronto:I have a wisteria in my backyard for 10 years, the plant is very healthy and gives me lots of leaves every summer but no flowers. My backyard is facing the east and enjoy sunlight several hours a day. I don't know what to do.

Marjorie Harris: Wisteria can break your heart. It should be blooming by now. Immediately: cut out a lot of that vegetative growth and start bringing it back to a good form. This may force it into a tiny bit of blooming this year. Next spring, cut it back drastically in March down to two buds away from the main stems. This may terrorize it into blooming. I've heard of root pruning to do the same thing but if none of this works just enjoy those lovely leaves. They really do like a lot of sun and warmth on their backs.

Lorraine Goorew, Prince George, BC: Marjorie, How do I stop the suckers coming into my lawn from a lilac bush that I have? I keep cutting them but they just keep coming!! Thank you.

Marjorie Harris:You just keep on pruning them out right to the ground. Take out some of the lower branches of the bush and re-shape it into a more tree-like form. This may discourage the suckers as the energy goes into making it form new branches. They are a mystery.

Branko Vukicevic, from Toronto: Hi Marjorie, I have a lemon and tangerine tree in a pot that grow fruits to approx.1/2 in size and then just drop. They have enough sun and plant food. Please what is the problem.

Marjorie Harris:I am not an exotic plant grower but you really need to grow a variety that will thrive in a pot. Improved Meyer Lemon will apparently. It needs a very large pot, lots of compost and and lots of water. And of course to be brought indoors for the winter. Check out web site recommending citrus in containers.

Maggie Nighswander, Winnipeg: Hi Marjorie, I live in Winnipeg, zone 3, and have a problem Mockorange. It lived in a shady location at my parents place for 3 years before coming to my garden with much more sun in spring 2005. It transplanted very well and had a beautiful show of flowers last year but this spring it appeared that the entire middle section had winter kill while the outside branches seem okay - they flowered decently. I cut out most of the branches leaving a few in case something changed and there are a few new branches coming up. Any suggestions for revitalizing this gorgeous plant? thank you. Maggie

Marjorie Harris: Just cut the whole thing back practically to the ground. This kind of dramatic coppicing will mean it throw strength into the roots and will come back much stronger and will have adjusted to your site. Do this in late June or early July next year. Add masses of compost around it. Greedy thing that.

Kevin Best, Vancouver: Do you have any advice for getting rid of bindweed? The previous owners tolerated it to cover some chain-link fencing, but it is getting everywhere. I have read the best remedy is to let pigs loose in your yard for a while to eat up the roots, but I think that would be frowned on in urban Vancouver : ) Also, I planted some acanthus spinosa last year. They too are rumoured to be invasive, but quite the opposite happened - the plants only produced a couple leaves each, which developed some yellow and brown spots. They are on the west-facing front of our house but fairly shaded by some healthier neighbouring plants. Any thoughts on how make them happier and see some flowers?

Marjorie Harris:Bindweed:; don't poke or pull at it. Cut it back to the ground, cover it with layers of newspaper (dampened) and then plastic. Acanthus mollis is invasive in the south of France. Move them out into the sun and they'll do better.

Dennis Harris, Ottawa: Hi Marjorie; I have a Japanese Lilac tree which has several vertical splits in the bark, each about six inches long. The tree is otherwise in great shape, and I understand these trees have a reputation for being very robust. Should I be concerned about the splits in the bark, and if so, do you have a remedy? Thank you. Dennis Harris Ottawa

Marjorie Harris:Alas we're finding that this tree isn't quite as robust as once thought. It is not tolerant of pollution. Splitting in the bark could mean something's going wrong. If you are truly concerned, get a certified arbourist in to look at it.

Kevin Best, Vancouver: Do you have any advice for getting rid of bindweed? The previous owners tolerated it to cover some chain-link fencing, but it is getting everywhere. I have read the best remedy is to let pigs loose in your yard for a while to eat up the roots, but I think that would be frowned on in urban Vancouver : ) Also, I planted some acanthus spinosa last year. They too are rumoured to be invasive, but quite the opposite happened - the plants only produced a couple leaves each, which developed some yellow and brown spots. They are on the west-facing front of our house but fairly shaded by some healthier neighbouring plants. Any thoughts on how make them happier and see some flowers?

Marjorie Harris:Bindweed:; don't poke or pull at it. Cut it back to the ground, cover it with layers of newspaper (dampened) and then plastic. Acanthus mollis is invasive in the south of France. Move them out into the sun and they'll do better.

Dennis Harris, Ottawa: Hi Marjorie; I have a Japanese Lilac tree which has several vertical splits in the bark, each about six inches long. The tree is otherwise in great shape, and I understand these trees have a reputation for being very robust. Should I be concerned about the splits in the bark, and if so, do you have a remedy? Thank you. Dennis Harris Ottawa

Marjorie Harris:Alas we're finding that this tree isn't quite as robust as once thought. It is not tolerant of pollution. Splitting in the bark could mean something's going wrong. If you are truly concerned, get a certified arbourist in to look at it.

Rasha Mourtada, Globe Life web editor:Thanks, Marjorie, for answering reader questions today. To our readers, look out for future gardening discussions with Ms. Harris.

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