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Back to Q & A: about Fragrant Olive (Osmanthus fragrans); fertilizer for Petunias and other annuals; and some problems and concerns from mid-Michigan.
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

May 25, 2014

Above, a close-up view and one of the overall shrub of Osmanthus heterophyllus; followed by one of a younger bush of O. delavayi. Below, a typical 1 kg container of Plant Prod 15-30-15 and an old shot of the Wisteria sinensis growing on my Toronto house in the early 2000s. The Weeping Larch is also in this photo at about the middle both left to right and top to bottom. Author photos.


Just this past Wednesday, Jim Glassford wrote as follows: “We live relatively near to you (Dorcas Point Rd. Nanoose Bay) and the arborist Wade Stewart just lives around the corner. We live on some acreage on the water. My wife is a retired surgeon and a master gardener. Do you have any idea where one might purchase Osmanthus fragrans as we would like to add it to our plant collection? Thanks!”

The one thing you have not told me, Jim, is whether Osmanthus fragrans is the only Osmanthus you will accept, or whether one of a couple of other species (which also grow here) would suffice. For example, in our garden here, we grow both Osmanthus delavayi and O. heterophyllus. These look similar and flower at just about the same time. They have just finished for this year. Sometimes there will be a few more flowers later in the year.

As to availability, I would try the folks at Art Knapp in Nanaimo, or you may have to go as far as Dinter Nursery, 5 km south of Duncan. If no luck, it becomes a case of checking out all the various nurseries in the area. If you absolutely cannot find O. fragrans, drop me another note and I’ll make some more suggestions.

One of my high school friends, Carol Hallam wrote a week ago with the following note:

“I just spent a morning at Vandermeer Nursery in Pickering with my daughter. We had a wonderful time, looking and buying—there is such a wide variety to choose from.

“Now, here I am (as usual) with a gardening question...I bought Surfinia Petunias (Bouquet Salmon and White Improved) and am quite looking forward to seeing them thrive. Thankfully they (supposedly) need no dead-heading!

“My question is about the appropriate fertilizer to use--What is your opinion about Miracle Gro All Purpose vs. Miracle Gro Ultra Bloom? Instructions with the plants indicate to feed every week with a “well balanced liquid fertilizer”—whatever that means. (Having dropped chemistry at good old East York Collegiate Institute, I don’t understand the NPK ratios!!) Maybe there is a fertilizer that would be better.

“I do hope you are well...these advancing years present lots of aches, pains, etc. As someone said ‘getting older is not for sissies!’ Bye for now from damp, rainy, and very cool Toronto.”

Always good to hear from “old” friends like Carol! Let me first offer the true definition of a ‘balanced fertilizer’. Many, many people think that only a fertilizer with an analysis like 20-20-20 or 15-15-15 is balanced but that is incorrect. A balanced fertilizer is simply one that contains some percentage of each of the three prime ingredients: Nitrogen, Phosphorus, and Potash. The ratio is different for varying crops but generally for annual or perennial flowers, one with a high middle number is preferred because it is the phosphorus that feeds the flowers (and seed production).

While I have nothing against or for any particular brand of fertilizer, I tend to lean to the brands that are manufactured here in Canada. I am still a promoter of the old Plant Products line of soluble fertilizers, which are still available all across Canada. Though the company is now in the hands of relatively new (Canadian) owners, their products are still of the highest quality. For your Surfinia Petunias I would be using Plant Prod 15-30-15, applied about every two or three weeks.

Best wishes, of course!

Katy Gardner of mid-Michigan in the U.S. wrote with some interesting comments and a question or two. Herewith: “Thank you in advance for your time. I love the landscaping surrounding your door with the awning. I ran across it while looking up images of Aunt Dee Wisteria tree. I could not tell from the photo what the trees and shrubs are, other than the wisteria. I am particularly interested in the weeping evergreen. I landscaped our entire property a few years back. I researched as much as possible, taking into account wildlife, soil, etc. and two herniated disks later, I am still not done.

“I love landscaping but need to simplify as I am spending all of my time trying to maintain and cannot keep up with the weeds. I think that I tried to do too much at once. What I have going here could use a crew but I want to adjust it so that I can handle the maintenance myself. I used a variety of evergreens (many are brown after this winter and may need to be replaced), perennial bushes, plants, vines and groundcover.

“One of My wisteria vines has morphed into more of a tree or bush and I am not sure what to do with it at this point as I do not know how large it will grow in this form. It is tall and skinny with a lot of branches from the ground up. It is planted very close to the house (i.e., 2 feet away) with a SE exposure. The wisteria is the least of my issues really. I have a lot of deer and other wildlife (Sandhill Cranes with their chicks) so I do not use fertilizer but do amend the soil when planting. Many of my plants and trees seem to be just surviving rather than thriving, especially the evergreens (however the different vines that I have are doing really well overall). The soil here is mostly clay with some sand (thus the herniated disks and hip problems from jumping up and down on a shovel in soil that was like concrete summer after summer). I am nearly 50 and at this rate, I will be gone before I ever see all of my hard work come to fruition.

“If you have moment, could you please lend me the benefit of your knowledge--any information or tips would be greatly appreciated. I just need an overall approach or adjustment. I live in mid-Michigan and have used the gardening book designed for this area and parts of Canada as my bible but the books can't substitute wisdom from experience as to how to get a handle on things. I am in over my head. I am thinking that perhaps I should use large, low, fast growing shrubs as it looks like you have rather than dealing with the weeds, groundcover and plants for some areas. I can't use arborvitae because of the critters. Thanks again!”

Well, Katy, first the weeping evergreen that was in our front garden in Toronto was a Weeping Larch (Larix decidua ‘Pendula’). That should be hardy with you in Michigan, and since it is deciduous, the deer won’t bother it at least in the winter!

Wisterias are a problem plant without question! Their ultimate height depends on the type they are. The Chinese Wisteria (Wisteria sinensis) can attain a height of 25 metres, whereas the Japanese version (Wisteria floribunda) grows only to a height of about 10 metres.

Pruning is another topic altogether! Wisteria is a very aggressive vine/shrub; once the initial growth becomes woody, little if any artificial support will be needed. The vigour of the plant, however, is not to be denied! You will have to prune the plant hard twice each year once it is established. In the summer you need to remove completely (2/3) or shorten back (1/3) to about 25 cm (10”) all the young thin green growths (which some call tendrils). You can actually do this several times through the summer, and at the same time direct the growth of the main branches so the plant, more or less, grows where you want it. It’s not necessary to cut all of these young spindly new growths back to the main stem, in fact you should leave some (1/3) of them at a length of about 25 cm (10”) from the main branch.

Then in early spring, likely in mid to late March, you prune again--at that time all the woody side shoots should be cut back to about 20-25 cm (8-10”), just ahead of a large bud. At that time you will already see many growth buds, but also possibly a few that are larger and appear like small acorns on the branches. These latter will be flower buds and you definitely should not cut them off. This pruning should aid the plant in blooming.

Unless the plant you buy in the spring is actually in flower, you may have to wait several years for flowering. The Japanese type (Wisteria floribunda) produces longer slender panicles of bloom, is capable of growing to ten metres (30’) and is usually considered slightly hardier than the Chinese cultivars that have slightly ‘fatter’ and shorter bloom panicles on much taller trees/vines, to 30 metres (100’).

You made one comment in your letter that concerned me—that you don’t apply fertilizer but rather just amend the soil at planting time. All plants require nutrition and in my opinion, the single best way of accomplishing that in any garden is through the application of liquid (soluble) fertilizer by means of a hose-end applicator. My comments to Carol above apply to you as well.

These fertilizers are not going to hurt anything and will give you much better growth than what seems to be happening now, according to your description.

I think that answers some of your specific questions; if you have others, just drop me another note.

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