Documents:

Goldenrod, Ragweed, Laurel & Other Questions

A question about goldenrod, and my comments on it vs. ragweed; problems with spotted laurel and a comment on its hardiness; and controlling sow bugs and raccoons!
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


September 10, 2006


Above, spotted laurel (Aucuba japonica) growing in Laura Grant’s Toronto garden—yes it is hardy but might suffer in severe winters and a lovely ragweed plant that should be pulled out. Below, Canada goldenrod at its best now.

An old friend in Toronto, Stan Bradley, wrote this week with a question that, at this time of year particularly, is a concern to many people. Here it is: “Hi Art - any idea what this is? It's growing about 6 ft. tall and I have no idea how it got there. I thought it might be goldenrod to go along with the millions of weeds that we seem to have this year. Thanks!”

Well, yes, he’s definitely correct, and here was my response: “You’re right--it’s goldenrod, which is NOT a contributor to the problems hay fever sufferers have at this time of year. The prime culprit causing hay fever is the pollen from ragweed (Ambrosia artemisiifolia).

“Goldenrod is sold here abundantly as a good fall perennial, but in Great Britain it is more highly rated than here. There are a number of different types, some more compact than others. If, as the yellow fades, you trim off all the old flowers, the seeds won’t develop and you’ll have many fewer seedlings the following year. I wouldn’t necessarily cut the plants right down, just remove the seed heads. The tall plants can look quite dramatic when covered with fresh snow in the winter, and the plants may be cut right off come spring.”

It’s likely that the plant Stan has (see photo) is Canada goldenrod (Solidago canadensis) which makes an excellent colour presence at the back of a perennial border in the fall.

Regarding hay fever, if you see plants of ragweed anywhere, do pull them out. The photo above is one I took right in front of an urban home in Toronto years ago.

Hendry Stark from somewhere here on Vancouver Island wrote a week ago: “I was given some cuttings of a type of Laurel that is the type with the spotted leaves. These cuttings grew exceptionally well and I transplanted them where I planned for my hedge. All of the seedlings took and seem to flourish however the tips of the leaves turn black and die; they do however come back again and the process seems to repeat itself. The soil is exceptionally poor; when planting the seedlings I dug down two feet and filled the hole with good top soil and steer manure. Thanks for any advice.”

It’s always difficult identifying plants from verbal descriptions, and even worse trying to identify insect/disease or other cultural problems. First, let me suggest that the plants Hendry has are likely spotted laurel (Aucuba japonica) and quite possibly the cultivar A. j. ‘Crotonifolia’. If that is what they are, the one possible cause of the tip die-back on the leaves would be excess moisture in the soil. Now, these plants will tolerate even the poorest of soils and even in shade (where they provide some welcome ‘brightening’) will grow well, but they do NOT like damp soil persisting. I suspect if Hendry has a heavy clay soil, and it was excavated in favour of top soil and manure, a type of French drain may have been created which is holding too much water. It is also possible the steer manure was too fresh and is causing the tip die-back. My suggestion is to check the amount of moisture around the roots, and if that is the case now in our drought season, that some form of drainage be provided so the roots do not sit in water. That will be particularly important for the upcoming rainy season here on the Island (rain here!).

Possibly of interest to Ontario readers, many folks do not grow this excellent shrub because it is generally not considered hardy even in southern Ontario, and thus hard to find in nurseries. My friend Laura Grant has grown one in her Toronto garden for many years, and I’ve included a photo of it (during the winter) here with this item. Unfortunately I cannot find any source of the plants in Ontario although plenty of nurseries here do sell them. It is seen for sale as an indoor plant there but those would not be the best to try outdoors; rather obtaining a cutting from someone already growing it outdoors, or a particularly hardy one from a B.C. nursery would be better ways to go.

More recently, Carol Peckford from nearby Qualicum Beach wrote with a couple of difficult questions: “Really enjoy listening to your garden show and.....tho' I know you're extremely busy and can't answer everyone's gardening questions, I hope you can help me with these two problems. I have zillons of sow bugs and tho' people say they are harmless they are devouring my strawberries and climbing up my trellis and eating my grapes. Any suggestions? Also, the raccoons eat my grapes. Any suggestions? I only have one little grape vine and we really look forward to the treat when they are ripe. Thanks very much.”

Sow bugs are perhaps one of the most annoying insects and yet as Carol says, they are basically harmless. I should point out that if you have rhododendrons that are being attacked by the black vine root weevil (half-moon shaped ‘bites’ on of the outside edges of the foliage) one of the best controls is NOT to apply insecticides, and rather let the sow bugs live happily in the surrounding soil as they seem to control the weevils about as well or better than anything else.

If you wish to try and control sow bugs the chemical permethrin (the manufactured copy of the natural pyrethrum insecticide) will work well. I suggest the Doktor Doom House and Garden insecticide which you will find at the Buckerfields store in Parksville. There is a bit of residual action in that aerosol product and it should help you.

Well, what can one say about raccoons, especially eating grapes. We have a large purple seedless variety here and they come in almost every year (the raccoons that is). The only thing that can be totally successful, which I have seen done in more than one garden, is to somehow enclose the vine in chicken wire so the grapes are produced within the wire. Unfortunately the nylon netting which is readily available in garden centres does not work as it is not as stiff as the wire and is thus easily manipulated by the raccoons. Good Luck!

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