Documents: Garden Design:

A Weed - No, A Perennial, Delphiniums, Hydrangea & Passionflower Vines

You’re kidding--our ‘weed’ is actually a perennial; care of delphiniums; weeping mulberry trees refusing to weep; Hydrangea shrubs prefer at least half sun; and where oh where are passionflower vines for sale
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

July 26, 2009

Above, Three shots of toad lilies, the first courtesy of John Kool, and the other two from our garden here in Parksville; followed by a shot of some newer Delphinium cultivars at Heritage Perennials test facility in Abbotsford, B.C.; and the newer D. ‘Red Caroline’ which is difficult to source and not so easy to grow as most others [photo courtesy Donna Dawson]. Below, a typical weeping mulberry followed by a huge passionflower vine growing on a 14th floor balcony in Toronto, note the road in the background is the infamous Don Valley Parkway; and a shot of a flower from the spectacular Passiflora coccinea. Author photos except P. coccinea (UBC Botanical Garden) and D. ‘Red Caroline’.

A number of varied questions this week; including this first one from John Kool in Hamilton Ontario. John wrote to Donna Dawson: “Do you know someone who can help me identify this horrible weed that has been haunting me for several years. It comes up every spring all over the garden. I have tried everything to get rid of it to no avail. The roots are quite deep (about 8 to 12 inches and are like large octopus tentacles. None of my neighbours have this weed. Thank you in advance...I enjoy your site. Cheers.”

My response was as follows: “It is Tricyrtis hirta, which is only a weed when it over seeds, as it loves to do. Commonly referred to as toad lily, it blooms in late summer and the flowers are like tiny orchids. Many people love it in their garden, and in fact most of the perennial growers now feature several newer cultivars with different-coloured flowers. It should pull out fairly easily—it does in my garden, when it overdoes its welcome! Or, you can use 2,4-D on it if you don’t mind breaking McGuinty’s stupid law.”

John last Saturday wrote back saying, “Thank you Art & Donna for solving the mystery I have been pursuing for a long time. I will probably let them grow now. Cheers.”

The next inquiry is also from Hamilton Ontario. Diane Church wrote: “I have a giant Delphinium (first year for it) and it was full of blooms. I need to know how to take care of it after it has stopped blooming. Do I cut it back or let it die off when the cold weather comes?”

If you cut each of the flower spikes of your Delphinium down to the main stem, immediately that the blooms are finished (or you cut the spike of flowers for use in a vase indoors), you should find that you will get some amount of re-blooming in the late season. This, to some extent, depends on the cultivar, but generally it works. An application of a liquid fertilizer to the foliage right after blooming will certainly not go astray either. Once the first frost strikes you may either leave the stalks to be cut down early the next spring, or cut them down in the late fall.

The plants should not require any extra winter protection in your area.

Rosemarie Staples of unknown location wrote to Donna Dawson with this question last week: “I bought two weeping mulberry trees last year. They are not doing the weeping thing they are growing branches that are going straight up and not weeping. Help, don’t know much about these trees. Thank you.”

Weeping mulberries are nearly all grafted trees these days, that is to say, a piece of a well-branched small tree is grafted atop a tall single-trunked mulberry tree. It could be added that the piece grafted onto the trunk is really an upside-down graft in order to create the weeping effect. When these trees start growing upwards instead of weeping, it is important to cut off all upright-growing shoots and branches, in order to encourage the weeping branches. Some-times the grafted portion dies, and hence the tree reverts to its totally upright growth.

Beware that if all of the grafted variety has died, the re-growth of the upright-growing Mulberry will end up as a fairly fast-growing (short-lived) tree at least six metres (20 ft.) in height.

Also this past week Debby Johnson of Winnipeg wrote with this question: “My question is about hydrangeas. My neighbor has bought two plants and placed them on the north side of their home. We live in Winnipeg, Manitoba. Sean and Julie are first time home buyers and she loves these flowers. They have never grown them before and neither have I. Sean asked me to look at the plants this morning because they do not seem to be growing well. I noticed small black dots on the bottom leaves and also new growth leaves are curling up. I checked for eggs or bugs but did not find any. We were hit with hail a week ago and there are the usual torn leaves that we see after such a storm. I do not think the black dots and the curled leaves are a result of the hail. Because I have little experience with these plants I thought I should ask the pro! I do not know the type of hydrangea but could find out for you.”

I think one of the problems the Hydrangea shrubs have is too much shade--on the north side of the home. Some hydrangeas (H. M. ‘Annabelle’ for example) will take that shade, but even those prefer a little more sun than adjacent to a house on the north side.

As regards what sounds to be insects, it is difficult to say just which it is, but I would suggest spraying the plants with Doktor Doom House & Garden Insecticide. That should get rid of whatever they are.

Irene Morris, of Vancouver, wrote to me with this next question, and I may well not be the best person to whom to pose this question: “I have lived in Vancouver all my life, but last year when my husband retired we moved to Golden, B.C. I had a passion flower vine in a large pot that I had nurtured for years and in the summer put it outside. It even bore fruit. I foolishly put it in the ground over last winter and it perished. I am trying to replace it but am having trouble finding one. Could you help me find a location to buy a passion flower plant? I am happy to pay the ship-ping costs as Golden doesn't seem to have any of these beautiful plants. Help!”

My suggestion is that you contact Brian Minter at Minter Country Gardens (1-604-792-6612) and enquire whether he has passion vines, and if so which one(s). The common or blue passionflower (Passiflora caerulea)--see accompanying photo--is likely the one you had, but there are several others including P. coccinea which is a delightful orange red colour. I did check with a number of garden centres near you but none of them carried them because they are not hardy outdoors over the winter there. However, we grew several in Toronto and kept them over the winter in a cool basement plant room.

In Vancouver, you might well have been able to keep them over the winter in the ground through most years.

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