Documents: Special Interest: Seeds, Bulbs & Such:

How to Rejuvenate a Cotoneaster Hedge
by Art Drysdale
by Art Drysdale

email: art@artdrysdale.com

Art Drysdale, a life-long resident of Toronto and a horticulturist well known all across Canada, is now a resident of Parksville, British Columbia on Vancouver Island, just north of Nanaimo. He has reno-vated an old home and has a new garden there. His radio gardening vignettes are heard in south-western Ontario over radio station Easy 101 FM out of Tillsonburg at 2 PM weekdays.

Art also has his own website at http://www.artdrysdale.com


July 4, 2010



Above: an example of “laying the hedge” as done in England. Note the cuts made in order to ‘bend’ the major trunks down near the ground. Photo courtesy National Hedgelaying Society. And, a shot of Cotoneaster lucidus with its spring flowers. Photo courtesy Wikimedia. Below, two shots of Cotoneaster horizontalis and one of Cotoneaster hybridus ‘Pendulus’ grown as a standard in the author’s garden in a much milder climate than Calgary! Author photos.




Two more letters this week, one to Donna Dawson at ICanGarden.com, and one directly to me. I think I shall have to leave the one to me, about dogs and lawns, until next week!

The one to Donna came from Marva Berniko who hails from just north of Calgary. Here is her first letter: “We have a cotoneaster hedge that is probably about 25 years old. It is above my head, so maybe is about six ft. tall. The last few years, it has not been doing so well. I read up on the fire blight, which is common to cotoneasters and our hedge doesn't seem to show signs of that. It's just that so many of the branches are drying up and dying. The hedge is get-ting very thin, more on the south and west where there are trees in the neighboring yards. There are several poplars on the south and one pine tree on the west, one willow tree and another willow that is dead now. I know poplars really sap the water from the lawn, so is that the problem? The east side isn't as bad, but it isn't as nice as it used to be. I'm often breaking dead branches out, but in doing so, the hedge is getting quite see-through. I'm really worried about it, as they take so long to grow that tall and we want it for privacy and to keep our small dogs in and others out. I can't imagine if we'd have to cut it down! We have it trimmed once every summer, if you need to know that.

“Do we need to give it nutrients and if so, what should we give it? How often? Is it beneficial to cut as many dead branches out as we can or should we just leave them? What do you suggest we do? Is there any help for it? Do we just wait and the new growth will eventually fill it in again? We just don't want it to die. The leaves look healthy enough, as far as I know, so maybe we just need to give it more time. We did have some drought a couple years ago.

“We live 60 miles NE of Calgary, AB and I think we are zone 4. I think Calgary is just a little bit warmer than we are. I don't know what other info you need.”

Since Marva did not say just which of four hardy Cotoneaster species that can grow in Calgary (actually zone 3a) I thought I would ask her that question before replying. I did also make the following suggestion: “I think likely a severe cutting back, either early next spring, or very soon now may well be in order.”

Marva got back to me the next day and here is part of her response: “Our hedge has filled out quite a bit more since I first emailed you weeks ago. Summer was late in coming and it was cold so long. I'm still concerned about it, as it is too sparse and I don't want it to keep getting worse. If you still recommend a severe cutting back, just how much do you mean? We don't have much knowledge when it comes to gardening and need to know details. Thanks for your help. It's much appreciated.”

I’ll try and answer some of Marva’s ‘side-questions’ first.

Fire Blight is a serious disease of nearly all members of the Rosaceae family--some more than others and the effects on the subject plants also vary. On top of that, there is a definite difference in the number of infestations in Western vs. Eastern Canada--I never saw Cotoneaster suffer from fire blight during my 40+ years in Ontario although I did see plenty of it on fruit trees, pears and apples for example.

If you see dying branches/stems, and there are swellings on the stem just above where the leaves started to die, you then have fire blight. If not, you probably do not.

Fire blight can affect certain Rosaceae trees very quickly. For example, I have seen Mountain-ash trees (Sorbus aucuparia) turn totally brown and die all within ten days to two weeks. On the other hand I have seen it affect pear trees by blackening certain branch tips, and provided those are removed as soon as they are noted, the tree itself has survived.

You mention the constant presence of dead branches, and yes you should remove as many of those as you can several times each year.

As regards moisture, since your plants are relatively old, they should have sufficient root systems to take up enough moisture, unless there is a prolonged drought. A soaking using a soaker hose during periods of drought would certainly not go astray.

You also mention nutrition, and yes, depending to some degree what your soil is like, it should receive some fertilizer every year. Early spring would be a good time for that as well. You could apply a high-Nitrogen granular fertilizer (high quality lawn food) on the soil under and coming out at least 45 cm from the centre line. I realize it may be difficult to accomplish that on your neighbour’s side, but it really does need to be done there as well. The alternative, perhaps slightly more expensive, would be to spray the new foliage sometime in May when it is all unfurled with a liquid fertilizer, such as a 20-20-20 concentrate that can be applied with some type of hose-end sprayer. I would do that at least twice in each spring. (The granular application would likely only need to be done once each spring.)

As I mentioned in my initial response, I think your hedge needs to be cut back, perhaps quite severely. Just how severely really depends on you--and what you can withstand from a lack-of-privacy point-of-view. The more you cut it back, the more vigorous it will become. I guess I would cut it back at least by one-half--that would still allow you some privacy and keep your small dogs in (and others out). On the other hand, if you feel like getting drastic, you could cut it to all but the major trunks and cut those off at least 30 to 45 cm (12-18”) from the ground. If I was going to go that route, I think I would wait until next spring before any of the leaf buds open.

There is still another operation you might wish to consider--it’s called “laying the hedge.” This is an old English idea, still being practiced in that country (which, of course has thousands of hedgerows) and instead of cutting the main trunks down to near the ground, you cut them to about 2 metres high, removing most of the side growths. Then you go along the hedge and cut part way (not all the way, please) through each trunk allowing you to bend each over to almost horizontal (perhaps at a 30o angle to the ground). These horizontal stems are then pegged in order that they stay in place.

The result will be a huge number of new growths out of the horizontal trunks which will grow perfectly straight up and can be pruned annually to make a better, more solid hedge.

This seems to be done at varying times of the year in England, but I would suggest doing it only in the early spring in your climate.

Annual prunings such as you are having done now will only contribute to a less effective hedge because you will tend to have mop-head bushes (trees) with little or no growth further down, where you likely need it.

I hope this long-winded reply helps!

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