Island fences

We have a home in Bourbonnais that is new construction and a blank slate. We are going to put up a PVC privacy fence and had a landscape plan for our backyard done through a local firm. We originally were not thinking of a fence but have changed our minds since the plans were done... My wife and I are thinking of placing trees and shrubs to sort of weave in and out of the fence line to look as if the fence was added after the plantings so it would look natural and blend in. What do you think? F.S., Bourbonnais

While most people prefer to place a fence directly along the property lines, we are fond of ‘island’ fences that appear to be seated amid the landscape plants. This type of fencing should be placed at least 10 to 15 feet inside the property line to leave enough room on the outside for small trees and shrubs or ornamental grasses. Apart from the obvious advantage of an aesthetically pleasing fence, island fences are also easy to maintain from both sides.

If you have not already chosen a fence style, consider selecting one that has an open pattern at the top. This will allow for more air circulation and light to reach plants. It also provides a trellis effect for weaving roses or vines.

When the fence is installed, you have an opportunity to lay an 18-inch gravel path on either side to allow access to plantings and keep down weeds along the fence. We would group evergreen plantings in the corners and place several small trees in and outside the fence to soften the blank wall. Then fill in with mixed plantings of shrubs, grasses and perennials. Don’t use too many kinds of plants and repeat groupings for a sound design. Make your beds deep enough to allow the shrubs to attain their natural spread and shape. Although it seems like large woody plant beds would require more maintenance, the opposite is true. Nothing requires more time and grooming than grass.

Hardening off new plants

Each spring, I buy beautiful plants at the garden center and bring them home, where they immediately begin to die. In as little as two days, they wilt and drop leaves. By the time I plant them, they aren’t even pretty any more. What am I doing wrong? D.G., Aroma Park

Ninety-nine percent of the plants you buy at the garden center were grown from either seed or cuttings in the confines of a greenhouse. Greenhouse production is good because it allows us to buy early and to choose from stunning numbers of cultivars, but it has a small trade-off. Growers make every attempt to simulate outdoor conditions by circulating air, controlling temperatures and adjusting light, but the plants are not getting the same ‘hardening off’ treatment that they would get from nature.

When you bring that young plant out of doors it has not yet built up the waxy cuticle layer that protects the leaves against moisture loss from sun and wind. Paradoxically, it is only exposure to sun and wind that will develop this protection, but it must be introduced gradually. Additionally, the light soil mix used by growers can dry out completely in a matter of hours, especially in the sun. We all know what happens when we bring home the little pots and sit them along the driveway. They immediately blow over, dry out and become difficult to re-wet once they are thoroughly dried out. It only takes a day or two of this treatment to stunt their ability to thrive.

Set up a holding area to receive plants that you bring home. Ideally, it should be in shade, with protection from wind. Try using a large tray to hold the purchases so that water can be added and slowly taken up by the roots throughout the day. I use rolling metal carts to wheel my plants in and out of wind, cold and hot sun until they are hardened off. Hardening off should take about a week, depending upon the weather. Annuals and tropicals require more attention than perennials when newly purchased. (See next question) The sooner you can get the plants into the ground, the better they will fare.

Disappearing Canterbury bells

Two years ago, I bought several pots of Canterbury bells and planted them in a well established perennial bed. They bloomed wonderfully and achieved just the look I wanted there, but they never came back. Are they annuals? L.A.R., Kankakee

Canterbury bells are biennials, not annuals. A biennial grows from seed the first year, usually becoming a rosette shaped mound of foliage. In its second year, it flowers, sets seed and dies. The third year, the fallen seed germinates and a new plant grows. This cycle continues as long as the gardener doesn’t do two things. The first is to deadhead, or pick the flowers. If you pick the flowers, they can’t go to seed and the cycle is interrupted. The other is to use a weed-inhibiting product like Preen in the bed. Weed inhibiting granules can’t tell the difference between a weed and your favorite flower. Since you bought a second year plant that flowered and died, you may have had seedlings last year that you didn’t recognize as such. To get biennials that flower every year, try planting them two years in a row to get a steady supply of seeds each year. It should be noted that biennials sometimes behave like perennials and reappear several years in a row. Unfortunately, most spire-shaped, cottage garden flowers are biennials (foxglove, delphiniums, etc.). Try salvias for a similar effect with more longevity.

Planting dates

How early can I plant perennials? Do I need to wait until the frost-free date? M.H., Frankfort

No. Waiting for our frost-free date (May 15 for us, but we have had freezes as late as Memorial Day) is a good idea when planting tomatoes or basil, but perennials can go into the ground much earlier. Most garden centers start selling them in April. If the garden center has them displayed outdoors, they are probably hardened off enough to go into the ground as soon as you buy them. If they came out of a greenhouse, I would harden them off for a week or so at home before planting. If the foliage does get nipped back by frost, the plant will recover.

Petite ornamental grasses

I like ornamental grasses but I have a very small garden. It is in part shade. Can you recommend one or two that don’t get quite so large? Thank you. H.O.L., Manhattan

Hakone grass (Hakonechloa macra ‘aureola’) is a very good choice for small gardens, particularly those that are shaded. This somewhat oriental looking grass has yellow striped leaves and grows slowly to a mound of about 18 inches in height and 2 to 3 feet in diameter. The plants are not inexpensive and it takes patience to watch it mature, but the results are very rewarding. A plain green variety is harder to find, but also beautiful.

Another choice is Miscanthus sinensis ‘Morning Light.’ This selection of maiden grass has all of the grace of the species, but is smaller in stature. It has very narrow leaves that allow it to remain more upright in partial shade. (The wider the leaf, the more grasses will flop in shade.) It has shimmery variegated foliage and forms a dense clump up to 4 feet tall.

If you would like to try a large grass in a small space, look at Molinia arundinacea ‘Skyracer.’ Over time, this tall moor grass gets very tall indeed, sometimes more than 8 feet, but it is more or less transparent. The foliage mounds to about 2 feet and the flowering stems shoot up to about 6 feet, remaining airy and ‘see-through.’ Just one makes a nice accent plant.