Q & A
Toronto Star column – published May 4, 2013
Welcome to the month of May. Gardening month.
Long time readers of the Toronto Star will recall Fred H. Dale, a columnist who made a valuable contribution to the community of horticulture for many years. Each Friday he wrote a Star column of ‘questions and answers’ that I read religiously. As a Toronto area garden retailer I needed to know what Fred wrote so that we could gear up for the customers who came in on the weekend looking for the plants and supplies that he recommended in the Friday paper.
My column this week is a nod to our late friend Fred. The business of gardening is rich with questions. People rely on those of us with experience in this field to help them succeed in the garden.
Here are some of the most common questions this time of year:
Can I use the grass seed and lawn fertilizer that I have stored from last year?
If it was kept dry, yes. Temperatures do not change the efficacy of either grass seed or fertilizer, but moisture will. In the case of the seed, mice will wreak havoc but not change the germination viability of it either.
Can I plant now?
There is a loaded question. If you want to plant frost tender vegetables or annual flowering plants, you are best to wait until May 24 [a Friday this year, conveniently]. At about that time the threat of evening frost is behind us. It is helpful to have warm soil too, for many plants. So-called ‘hot crops’ like tomatoes and cucumbers thrive in soil that is over 18oC. There is no harm in waiting a week or two after the 24th of May if you are unsure.
All other plants can be planted now. Trees, shrubs, evergreens, roses, and perennials to name a few.
Can I prune my cedar hedge [or lilac, or maple tree] now?
Yes and no. You can prune up to one third of cedars any time of year. Now is as good a time as any, if it suits you. Evergreens lend themselves to spring pruning as most of their growth takes place in late May and June. The ‘flush’ of new growth always looks good after a haircut.
Flowering shrubs will not be harmed by a spring pruning BUT you will remove the blossom buds of spring from your permanent shrubs like lilac and flowering almond if you prune it just before it flowers. Remember this: spring flowering shrubs set their blossom buds in the autumn while late summer flowering shrubs set their buds late spring and early summer. You can’t go wrong by pruning a shrub within 6 to 8 weeks of its flowering period.
Trees are generally best pruned this time of year. Hardwood trees like birch and maple will bleed sap excessively if they are pruned while dormant. I recommend that you prune them while in full leaf.
Can I move my peony now?
Perennial plants can be moved now, but do not leave it much later. Peonies are quite forgiving if you move them in spring, but they prefer to be moved in September. Hosta, monarda, daylilies, and the like will move nicely this time of year but they will not be happy if you leave this job until they have a full head of new growth in the heat of early summer. Time is of the essence. Dig them with a garden fork or use a sharp spade or shovel. Once out of the ground cut them as you would a pie: once in half and then in quarters. Replant the divisions in appropriate locations or give away to gracious friends and neighbours.
How do I treat grubs in my lawn?
In the absence of a cadre of chemicals that were available at one time, we now treat the white and grey grub with beneficial nematodes. They are microscopic worms that feed on grubs and exist naturally in our soil. When you apply them from a sprayer you are intensifying the population in an effort to control the grubs in your lawn and garden. Timing is critical: spring is one period of application and the other is late August and September. The grubs migrate through the soil, moving up near the surface during these two windows of time, where they are most accessible to the killing machines that we call nematodes. After application, it is important to water very thoroughly to move the nematodes to the root zone –the feeding area – of the grubs.
How do I kill the weeds in my lawn?
This is the wrong question for today’s gardener. Now we talk about controlling weeds, not killing them. In the not so distant past we sprayed broad-leafed weeds with a 2,4-D based product and that was that. The weeds grew back and we sprayed some more. Now, we compete them out of existence.
It is easy to do this, it just takes some changes in how you care for your lawn and it also takes patience. Follow my recipe below and you will eliminate 90% of the weeds within two years. Not a quick fix, but a permanent one, which is more than anyone can say about chemical lawn weed control.
Cut your lawn 7 to 8 cm high. The higher the grass blades, the deeper the roots and more drought tolerant your lawn.
- Use a mulching mower. This returns the nitrogen-rich, natural goodness of the cut grass blades back to the root zone of your lawn.
- Apply a quality lawn fertilizer that contains high nitrogen that is slow release based. I use Golfgreen which has the most sophisticated form of slow release nitrogen.
- Re-apply fertilizer twice more throughout the season: once in late spring/early summer and again in fall.
- Water seldom but when you do, apply it deeply. As water moves through the soil to the root zone of your lawn, the roots will follow it. Again, the deeper the roots, the more drought tolerant [and strong!] your lawn will be.
- Where bare patches do exist in your lawn, spread 3 to 4 cm of triple mix or lawn soil over the area and broadcast quality grass seed at the rate of 500 grams per 40 sq meters [one pound per 400 sq ft]. Rake smooth, step on it to bring seed and soil in firm contact, and water thoroughly until established.
One word of warning: if you play golf, remember that it is unreasonable to expect that your lawn look like a fairway. Every golf course has a dirty little secret: the equipment shed. And there is a battery of people who arrive at ridiculous hours in the morning to use that equipment so that you can enjoy a great game. Let them maintain their turf their way and you yours, according to my recipe above. I guarantee that you will spend less time tending your own grass and more time golfing.
It is the first weekend of May and we will be gardening our socks off for the next few weeks. We have learned a lot over the years and as Canadians we have advanced in both our thinking and our practices. Thanks Fred.