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Have You Ever Heard Of Daisy Bushes, Or Olearia?
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 13, 2014



Above, Olearia x haastii and Olearia macrodonta. Below two different Olearia phlogopappa, ‘Comber Blue’ and ‘Comber Pink’.





 

Daisy bushes can make ideal evergreen shrubs for hedging or windbreaks in coastal gardens or landscapes, but likely only in the mildest areas of Canada and the U.S. This is what Miranda Kimberley had to say about them in the April 14 on-line edition of HortWeek from the U.K.

“Daisy bushes can make ideal evergreen shrubs for hedging or windbreaks in coastal gardens or landscapes, she explains.

“Olearia, or the daisy bushes, are some of the best evergreen shrubs for use in coastal areas, making excellent hedges and windbreaks. Some of the species also cope well with atmospheric pollution, making them versatile plants. Coupled with interesting foliage and often attractive daisy-like flowers, they can be a great addition to gardens or landscapes, though be aware that some of them are not fully hardy and may suffer from damage in cold, windy positions.

“There are about 130 species of Olearia, all hailing from the Australasian region, with a high proportion from New Zealand. They are all evergreen shrubs, some with the potential to grow into small trees, though in the UK the average height attained is 1-2.5m. There is quite a variability in the leaf shape and colour. Generally they are leathery, dark green above, with a silvery sheen or white downy underside. But they range from broadly ovate to thin, narrow and toothed. They tend to produce attractive corymbs of daisy-like flower heads, but some have quite small, inconspicuous flowers.

“Probably the best known in the UK is O. × haastii, which is hardy almost everywhere in the British Isles and proven to be an excellent hedging plant. It has small, neat, glossy green leaves with a white felted underside and is covered in fragrant flower heads between July and August. Another popular choice for hedging is O. macrodonta Award of Garden Merit (AGM), also known as the New Zealand holly because of its spiky leaves. They are an attractive sage green, with a silvery-white underside, and produce fragrant broad panicles of flowers in June. There are also smaller and larger forms of this excellent plant—‘Minor’ and ‘Major’—that are suitable in coastal regions.

“Other species are grown more for their ornamental value. O. ‘Henry Travers’, for example, has lovely lilac flowers that make the shrub resemble an aster. Others grown for their flower display are O. ramulosa ‘Blue Stars’, O. phlogopappa ‘Comber’s Pink’ and O. phlogopappa ‘Comber’s Blue’. Many varieties exhibit striking foliage forms. One of the best examples is O. × mollis ‘Zennorensis’ AGM, with its lance-shaped, sharply-toothed leaves that are olive green above and downy white underneath.

Olearia generally require a sunny position in well-drained soil. They do not cope well with waterlogging. Many species cope with windy, exposed sites but their hardiness limits range from -15°C to -5°C with a few borderline hardy types, so give these some protection from cold winter winds by planting in a sheltered location. They are said to do well in chalky soils. O. × hastii, O. macrodonta and O. traversii in particular make good hedges and windbreaks in coastal areas. Should specimens become straggly or untidy, they can be hard pruned in April.

“There are no particular pests or diseases that affect the genus.

“‘Liz Hughes, events and marketing, Provender Nurseries, Kent said: Olearia is a handy plant on many levels but mainly for hedging in awkward situations. We hold three to four different types in stock on a regular basis. These include O. × hastii, which is probably one of our best-selling Olearia due to the fact that it is happy in exposed conditions. We deal a lot with coastal situations and roof gardens, both of which require a plant that will withstand exposed positions and require little maintenance. O. × hastii only requires pruning once a year.

“‘O. macrodonta ‘Major’ is another popular choice among customers looking for hedging—although not as popular as O. × hastii—that is preferred for its smaller, daintier leaf. O. ramulosa ‘Blue Stars’ is a dainty ornamental type that sells really well when in flower.

“‘Olearia are happiest when they are planted in a well-drained soil—they suffer in waterlogged conditions—and they have generally survived happily in our UK climate, although gardeners may have suffered losses this last winter.’”

“Charles Carr, nursery director, Lowaters Nursery, Hampshire offered this: ‘We grow four varieties at Lowaters—O. arborescens ‘Moondance’, O. phlogopappa ‘Comber’s Pink’, O. × scilloniensis and O. × scilloniensis ‘Master Michael’. ‘Moondance’ is a new variety that we sold last year for the first time. This appears to be a very good variety with attractive variegated foliage. We encountered no problems with the production and found it to be a good grower. The other three on the list we have grown for many years and they are fabulous plants that we propagate on site. They make for strong plants with attractive foliage and are very free-flowering in April. This early flowering makes them great shrubs for early-season garden centre plant sales. We grow these in our peat-free compost and find them to be reliable, easy-to-grow shrubs.

"The only problem we encounter with them is thrip damage to foliage. The range of white, pink and blue offers the customer choice within the genus and we will continue to offer them in the future.’

“Here is what Kevin Ball, head gardener, Inverewe Garden (Inverness), Ross-shire in North-western Scotland has to say about the plants:

“‘Inverewe has held the National Collection of Olearia since the 1960s, where the collection thrives in the open, coastal windy aspect of the West Coast. They thrive here from within feet of the high-tide mark to the darker reaches of the woodland. I wouldn’t recommend too much protection—they’re not as tender as one would think. A few rank among the most beautiful flowering shrubs we can grow. I would recommend O. ‘Henry Travers’, a striking plant with attractive silver/green foliage and large blue/mauve flowers. O. ilicifolia is a good all-rounder with attractive corymbs of flowers that have a musky fragrance and silvery/grey wavy-edged leaves. At Inverewe it looks beautiful planted in a rocky scree with Celmisia and Aciphylla.

“‘O. hookeri is a compact shrub with a very unusual conifer-like appearance and striking lime-green/yellow flowers. Finally, a variety that makes a fantastic coastal flowering hedge is O. ‘Talbot de Malahide’—one of the toughest of all Olearia.’”

So, there you have it—a lot of information about a plant that may only be hardy in the mildest parts of Canada and warmer states of the US; but the mere fact that they grow well in North-western Scotland tells me that they certainly should be being considered in our climates out here on the West Coast. In fact, I have one report of some being hardy in nearby Seattle, Washington.

As to availability, the only supplier I have located in Canada is the well-known Fraser’s Thimble Farms on Arbutus Road on nearby Salt Spring Island, who do offer a mail-order service.

In fact, whether or not you are specifically interested in Olearia or not, if you are coming out to Vancouver Island for a visit, at virtually any time, I would highly recommend a visit to their three-acre nursery. Check out their extensive Website for full details: www.thimblefarms.com .

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