Three Varying Questions From Previous Years That Are Still Appropriate For This Year
by Art Drysdale
by Art Drysdale


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

April 28, 2014

Above, a large black walnut tree (Juglans nigra) growing in Toronto; and two shots of our deck on the waterside here, the first taken in July 2006 before the shrubs were planted around the base, and the second, in June the same year prior to the cleaning and re-staining. Below, two shots of Brunfelsia pauciflora, the first showing our plant not long after we obtained it in Toronto, and the second a close-up of the flowers on a plant in Hana, Mauii, Hawai’i. Author photos.


Again this week I am going to repeat here some questions I have received in recent years, knowing full well that many readers may have the same question on their minds.

The first this week is from Joe: “I have a huge problem with a neighbor’s Black Walnut (Juglans nigra) tree which is huge and is right up on the border line of his and my property.

It has killed almost everything in my back yard, and now I was wondering how Cedar hedging would do. The planting would start about 15 feet from the base of the tree, is there a chance they might grow ok ? Would love to get your opinion. Thank you in advance.”

This is an age-old problem dating back to the year 37 (yes 0037!) A.D. However, only in 1928 was the compound, juglone isolated in many plants in the walnut and hickory families, and found to be the cause of the death of other plants coming in contact with the roots of black walnuts, as well as butternut and hickories.

Although the poisonous compound is found in the roots, leaves, bark and husks of the nuts of the black walnut, toxicity is usually only noted when the walnut’s roots come in direct contact with susceptible plants.

Most people ask just what plants are susceptible. Actually, quite a long list including tomatoes, blueberry, apple, pear, blackberry, azaleas, rhododendrons, cinquefoil, red and white pine, and other evergreens are all likely to show symptoms, and eventually die. I would not want to suggest white cedars since I don’t have any reports on them, yay or nay!

As to plants that are not bothered, there is also a good list from which you may choose. First, the most obvious is bluegrass, it thrives! Many vegetables other than tomatoes are OK; for example, snap beans, lima beans, sweet corn, onions, and parsnips generally grow fine. Years ago, there was a report of beets with a strong flavour that may have been related to black walnut roots.

Some plants seem to be on the border line of susceptibility; ie. some times they are affected, and other times not. The explanation would appear to be the amount of soil moisture. Plants such as sweet peppers, lilacs and Viburnum (snowball, for example) may be affected in constantly damp soils, and not in open, dryer soils.

If it is flowers you’re trying to grow, stay away from peonies. But, you should have no difficulty with anemones, cyclamen, Hosta, Iris, Lilium, forget-me-nots, daffodils and narcissus, primroses, salvia, and, the most popular of all annuals (one that will grow well in the dense shade provided by a black walnut) all impatiens.

Incidentally, just removing a large black walnut tree will not guarantee freedom from the effects of the juglone compound in the soil. That could take at least another year, although killing the tree’s stump with an herbicide will give freedom from the compound faster.

And do remember, that it’s not just black walnut trees that contain juglone in their roots. A recent question had to do with a problem near a butternut tree. The gentleman said he was having trouble with rhododendrons. I told him I was sure that the problem was juglone.

Second for this week, from Cynthia Doerksen in Victoria: “Hello, I read your deck-building article, and have a few questions about how it is holding up. We are in the process of replacing our deck boards with pedra hardwood decking, and I would like to know how the Deckster brackets are holding up now that your deck is a few years old. Is there any rust on the brackets, is there any board movement, splintering, anything that you would do differently? We live in Victoria, and are considering the Penofin red label product for finishing—how is that holding up, how often do you have to refinish? Any helpful hints or suggestions would be appreciated! Thank you.”

When your question came in, it caused me to crawl under our deck (60 cm above ground!) to inspect the Deckster brackets. They were all fine, no rust or corrosion along with the screws which were also in good shape. There had been no splintering or other problems with the deck other than the Penofin stain, which I now certainly do not recommend for decks which are subject to the salt spray as ours are. We also used the Penofin stain on two smaller decks on the front and one side of the house. There it has worked out quite well, but on the main deck—not good!

After many back and forth phone calls with the manufacturer I decided to forget the product and we now use a Canadian product from Home Hardware which has worked out reasonably well. The one ongoing problem is federal regulations which are having all manufacturers eliminate all oil-based paints/stains in favour of the inferior water-based products.

Finally my third item this week, from Susan Paul in Vancouver: “I came across info about you while searching the availability of Brunfelsia pauciflora here in Vancouver. My mother has a shrub in her New Zealand. Love the scent and wondered whether it would have any hope of surviving our climate....could you keep it out in summer and bring it in in winter? I only have a small apt. Thanks for any info you may be able to give me.”

You are asking about one of my favourite indoor plants Susan. We have grown “Yesterday, Today,

Tomorrow” (Brunfelsia pauciflora) for several decades both in Toronto and here on Vancouver Island. It is definitely not hardy outdoors here for the winter months, but you certainly could put it out for the May to October period, and then bring it indoors for the balance of the year.

As to where you might obtain one, that is a more difficult question. Specialist nurseries are the only answer.

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