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Credit: Gillian Reece

Each time Dora Kreiss takes me through her quiet woodland garden overlooking the Strait of Juan de Fuca, I come away revitalized, for I am reminded of how rewarding retirement years can be.

Home to well over 400 rhododendrons, this magnificent Sooke garden is the retirement creation of Dora and her late husband Robert. The Kreisses began planting on their acreage 28 years ago, having first fallen in love with rhododendrons years before in the eastern United States. Later on, they were further inspired by the plants they encountered in the Rhododendron Species and Botanical Garden at Sea-Tac near Seattle, and indeed, though their collection does include some hybrids, it is principally devoted to species.

On my many visits to Dora’s garden I’ve discovered that these species seem to bloom in almost every colour of the rainbow. I was introduced to the red Rhododendron strigillosum so often used in hybridizing, while my eye was caught by the orange colouring of R. keysii. Sunshine yellow is imparted to the north side of Dora’s home by R. wardii; thriving blissfully in a rotting stump is R. davidsonianum in lavender, which may be as close as rhodos ever come to blue. On dreary winter days R. dauricum brings an unexpected blaze of magenta to the landscape, and later on R. arboreum ssp. cinnamomeum performs in pink.

The cinnamomeum epithet refers to the colour of the felt or indumentum decorating the underside of the leaf. This reddish-brown indumentum carries on the show when the blossoms of this cultivar retire; I discovered that R. tsariense wears its version of this “underwear” in tan while R. rosevallon has chosen hers in a rich wine red (though there’s some question as to whether she’s a species or a hybrid). Indeed, the Kreisses’ choice of plants had a great deal to do with foliage; they were especially taken with large leaves, such as those belonging to R. praestans.

Preparing the site for planting was no small undertaking for Dora and Robert. Though the land had been partially bulldozed to make way for the house, there were still blackberries, salmonberries and alders to be cleared away. Western hemlocks, Douglas firs and western red cedars were spared so they could provide the dappled shade required by rhodos. Because of underlying rocks and gravel there was no problem with drainage, but the soil did need improvement so the Kreisses brought in topsoil.

From the beginning, Dora and Robert converted unwanted vegetation into the compost that’s used to line the holes at planting time. Now Dora has a chipper and she chips spent fronds of sword ferns separately for use as mulch, after learning that the soil beneath these native ferns is especially rich.

After Robert’s passing, Dora was determined to carry on their labour of love. Weeds are an ever-present challenge, and although Dora tries to persuade herself that some ground-cover species are ornamental, she can’t quite come to terms with sorrel, trailing blackberry or lamb’s quarters. She does like herb Robert, miner’s lettuce and sweet woodruff, but they tend to collect around the irrigation emitters and aren’t welcome above the roots of her rhodos.

Dora has other jobs to tackle, too. She applies alternating sprays of Benomyl and Funginex to control mildew; she feeds her plants with 10-8-6 plus minor elements, a formulation recommended by rhodo specialist and friend Norman Todd. She tries to preserve the natural shape of her specimens, but does prune to take out low growth and to keep the paths unobstructed. She also deadheads so developing seeds won’t sap plant vigour.

Because I too am now in my so-called “golden years,” I’m full of admiration that Dora can still manage such an enormous garden with so little help. Dora does allow that she’s slowing down, but she still starts the day with a walk on the beach and then devotes the rest of the morning to her rhododendrons. As she says, she believes in exercise.

So I was mightily amused to hear that Dora had recently received a book on aging gracefully – it seems to me that she is well qualified to pen such a volume herself!

Norman Todd’s love affair with rhododendrons reaches back well over 20 years and so does his nursery near Victoria, which offers over 300 species and three times as many hybrids. I first became aware that Norman was an authority on rhododendrons back in the 1980s, after reading the many knowledgeable articles he was contributing to The Island Grower.

Norman’s interest in rhododendrons led to an eight-week workshop that he conducted with Dr. Dave Ballantyne at the University of Victoria in 1979, and out of it was born the Victoria Rhododendron Society, which became a chapter of the American Rhododendron Society. Norman teaches at the Horticulture Centre of the Pacific in Victoria and delivers countless lectures on his favourite genus to many garden-oriented groups. When I heard about his unorthodox approach to the feeding of rhododendrons, I introduced myself to Norman, who kindly took time out from his enormous nursery to fill me in on the details.

First of all, Norman divulged that if rhodos already reside in soil that is black, fertile, friable and rich in humus, they may never need supplementary feeding at all. But for those that are not so lucky, he’s developed a regimen that is no doubt responsible, at least in part, for the well-being of his own thriving collection.

Although most of us feed our rhododendrons only before and after flowering, they really need constant nourishment. During our winter rains, vital nutrients soon leach out of reach of the plants’ shallow roots, so Norman recommends a feeding every two months, beginning in November and ending on July 1.

The need for nutrients is largely governed by soil temperature and it doubles with every temperature increase of 10°C. For example, a plant that benefits from 30 millilitres of fertilizer in November could require double or triple that amount in May and July.

The fertilizer that Norman favours breaks with tradition in that it offers extra nitrogen, for he asserts that the notion rhodos don’t need much nitrogen is a myth. He uses the 10-8-6 formula developed at the University of British Columbia; in fact, he helped to test it before its release. This formulation contains all 13 of the elements rhododendrons require, and 50 per cent of its nitrogen is offered as sulphur-coated urea which is released slowly over a long period.

The most common reason for the yellowing of rhododendron leaves is insufficient nitrogen, and if they remain yellow after this feeding, more nitrogen can be applied using such acidic preparations as fish fertilizer 5-2-3 or Miracid 30-10-10. Or yellowing can indicate a shortage of magnesium, which can be supplemented with Epsom salts (magnesium sulphate), 15 millilitres in 4 litres of water. Epsom salts won’t alter the soil pH, which should register around 5.5.

If extra nitrogen and magnesium fail to green up the leaves, it may be that they’re not getting enough iron. Iron chelate is in order; the chelate chaperones the iron so that it won’t enter into mésalliances with other substances before being absorbed by the plant.

For those who’d rather use an organic fertilizer, Norman recommends the following mix developed by Allan and Liz Murray of Cobble Hill: 4 parts each alfalfa, canola and blood meals; 2 parts dolomite lime; 1 part each rock phosphate, bone meal, kelp meal and greensand. Apply mixture once a year and mulch the plants heavily with ground bark.

Norman warns that although this organic preparation offers the advantage of ongoing sustenance, it does take time to break down and release its nutrients. So if you’re switching over to organic feeding, do it gradually by overlapping applications of both kinds of fertilizers.

Barbara Chernick lives and gardens on an acre near Sooke, where for the last 12 years she has been writing a weekly garden column for the Sooke News Mirror.