Documents: Hot Horticulture Issues:

Three Questions from Readers

Hard-to-find Juniper cultivar; Growing of Bougainvillea vines indoors; A shrub changes from a white to pink flower colour; & finally does bamboo need protecting in Furry Creek?
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

November 4, 2007

Above, a display of three different cultivars of Bougainvillea taken at a garden centre in South Africa; and below, typical growth of a large shrub, this one on the island of St. Lucia. Author photos.

On the 25th someone in zone 5A with the moniker “mjmcanally” wrote with this question: “Does anybody out there in this gardening world know anything about Juniperus communis 'Arnoldii'. I have acquired a few which are quite beautiful but I do wonder about their hardiness in this 5a zone and do they need any winter protection. The fact that they are communis suggests they are as hardy as can be, but one never knows with these cultivated varieties? Thank you.”

Like the writer, I too could not find anything out about this particular cultivar. Since I was in contact with him on another matter, I posed the question to Allan Armitage who teaches horticulture at the University of Georgia, where he works alongside Michael Dirr. Both are prolific authors of highly authoritative books. Unfortunately at the time of writing this on Friday, I have not heard back from him. It may be that he has referred it to Michael Dirr and that he is having the same problem as the questioner and I!

Last Sunday, Joan Pogson from Victoria out here on Vancouver Island wrote to Donna Dawson with the following question, the answer to which likely could be applied to anyone in Canada! “Good Morning! My name is Joan and I live in Victoria, B.C. We have a large bougainvillea in our living room (south facing) It lives next to a baseboard heater. It is shedding leaves a little and looks a bit seedy. Are there any food supplements we need at this time of year? Thanks so much for your information.”

Joan, you haven’t given me nearly enough background information. For example, how long have you had this plant, was it outside during the summer, did it bloom during the summer, do you have any added humidity in your living room, etc.?

Bougainvilleas (named after a Canadian by the way, who was an explorer, mathematician and lawyer back in the late 1700s) are tropical vines that must have a maximum of sunlight--at least five hours per day. In the winter months you likely should not expect any bloom, and the plant could well go almost dormant, dropping all or most of its leaves. They also require humidity in the air, but they do not like growing in a pot that sits in water.

I would not fertilize it at all from now until likely February when you see new buds forming then apply a high phosphorus (middle number) fertilizer with plenty of micro-nutrients. Obviously they are not hardy outdoors over winter even in Victoria; in fact they don’t even like night temperatures below 15o C, and only grow well when the daytime temps are between 21 and 29o C.

Also last Sunday, Margie probably from somewhere in Alberta or B.C. wrote asking Donna the following: “Three years ago this year I planted a white butterfly bush. First year [it] was ok, last year it was so beautiful. I was so ex-cited to see it even taller this year. I waited and waited and finally when it came up it grew along the ground. The leaves were healthy looking and in very late summer it produced these beautiful PINK flowers - just tiny clusters. I was shocked! What happened? I tried to find info on butterfly bushes in general but can't seem to find the answers I want. I will have to see what happens next year. I also want to know how long they live?”

Folks, I want to make another appeal that when you write with a question, that you supply the name of the town/city from whence you are writing. Often it is ever so important if the question is to be answered correctly.

In this case, from Margie’s description, it sounds to me that she is in Alberta although I would not ordinarily expect the Butterfly bush (Buddleia davidii) to be hardy in any part of Alberta as it is considered a zone 5b plant and Alberta just does not have anything milder than zone 3b at the southern tip of the province. However, her mention of “when it came up it grew along the ground” makes me think that it did kill right back to the ground, and snowfall may well have protected the roots.

Now, what happened with the change in colour of the flowers is even more difficult to explain. It happens with all types of plants and when it does, the resulting change is generally (but not always) referred to as a ‘sport’ of the original cultivar. Another explanation often is that the original plant was either budded or grafted on a different (theoretically more hardy) rootstock. When that happens, often the budded/grafted cultivar dies as the plant is killed to the ground and the rootstock (with a different colour of flower and possibly a slightly varying foliage type) carries on. So Margie, one of those may be your answer.

Under reasonable growing conditions, Buddleia davidii are long-lived shrubs.

Just this past Thursday Sue Baker of Furry Creek, B.C. wrote with this question: “I have bound up the pots of my bamboo (I have 3) with newspaper and bubble wrap to help protect them from the wind whistling round the pots. I have moved them under the porch at the back door but they don't get any sun there at this time of the year. I could move them to the other end of my deck where they would be against the house with a tiny overhang from the roof line and get a little sun but not be as protected. Sooo, my question is: a) should I leave them more protected with no sun, or b) move them to less protected area but with a little more sun? Hope someone can help. Many thanks - Sue. P.S. Could you give me the correct name for this type of bamboo please?

Sue, I know when I drive to Squamish or Whistler on the famous Sea-to-Sky Highway, I pass a sign for Furry Creek. Depending how high above sea level you are, will govern just what Canadian hardiness zone you are in. But, right now, I would estimate it as zone 8a--and you should not need to protect the pots of your bamboo whatsoever in that climate. I would therefore put them in the sunnier area, but just for fun, put one pot in the slightly less sunny area.

As to which bamboo you have, I cannot tell from your photo. There are basically two types of bamboo, “running” which can be very invasive, and “clumping” which are not invasive. I suggest you check one of the many bamboo Websites such as or

  • New Eden
  • Kids Garden
  • Plant a Row Grow a Row