Especially exciting is a rare Canadian speaking appearance by renowned American landscape architect Wolfgang Oehme, pictured above. Together with James van Sweden he revolutionized perennial garden design in North America, introducing us all to ornamental grasses in the "New American Garden" style.

Wolfgang Oehme's lectures will take place Friday June 9 and Saturday June 10 at 2:30pm in the Lecture Hall of the School of Horticulture. Tickets are limited, at $25 each. For tickets call 905-309-3959.

I'll be there throughout the show, helping to keep the demonstration stages running smoothly, and please do say hello if you happen to go!

WINNER: Lorna — Calgary, Alberta
"I love growing perennials in containers! I start by making my own planters out of hypertufa [a mixture of peat moss, vermiculite and cement], that way I can make the container in any shape or size, though I try not to make them too big so I can move them around in my garden to create interest when other plants have finished blooming. I like to grow mostly small rock garden plants in my containers.

For sunny locations I've planted Lewisia, Gentian, Campanula, Jovibarba [a close cousin to Sempervivum] and Saxifrage. For shade areas I've grown dwarf Hosta anf ferns in my containers. To overwinter my containers, I dig a hole in a spare part of the garden and plant the pot up to the top edge. In springtime, I simply dig the container out and place it where I want in the garden. As you can see from the picture [see above] which I took today on April 17, my plants have survived another year in Calgary's cold winter climate. I've only lost one plant in my containers, a miniature yellow iris which my dog insisted on digging up!"

WINNER: Leslie — Ottawa, Ontario
"I love hostas in pots and since I have so many that are big and established, experimenting with them is worry-free. If they don't survive in the pots I have plenty to replenish. I have found that turning the pot with the hosta on its side [for the winter] works for the most part, although the plant isn't quite as lush as the previous season.

My best recommendation is a holding bed and a really large container. I have a holding bed on the side of my house. I keep all kinds of plants in there, some buried in their plastic pots, others without, which I use for seasonal adjustments to my containers. When their season comes, I pull them out of the bed and pop them in my large display container beside the fillers that I keep in there all summer, and voila — seasonal plantings. When their time passes I put them back in the holding bed and replace them with something else more seasonal. In my display container I keep an empty pot sunk down to accept these seasonal changes with minimal fuss. I can also pop in store-bought perennials and enjoy them for a month of show before I transplant them into my garden. All kinds of potential."

WINNER: Joan — Calgary, Alberta
"Here in Zone 3, I've been very successful overwintering Goat's Beard (Aruncus dioicus) in my garage. In the fall, once the frost bites, I trim off the foliage, drag the pot into the garage and place it in what we fondly refer to as the 'crypt' — a large area in the corner of the unheated garage lined with 1 inch styrofoam. I check and water it lightly in January, if necessary, and haul the pot out in April if I see signs of life. I keep it in a protected spot on our east-facing porch until the weather warms. For the rest of the summer it is watered and fertilized the same as other containers and repotted in fresh soil every couple of years.

Anne Marie — Toronto, Ontario
"My favourite potted perennial is my 'Gold Standard' Hosta [pictured here] which has been living in a terracotta pot for a few years. This experiment has been so successful that I have branched out to miniature roses and daylilies. Hens-and-chicks also grow beautifully in shallow containers. I keep the containers over winter in the basement cold room, which is cold but never freezes. I always take the containers out of the cold room in March to bring the plants out of dormancy a bit early so they can get an early start on the season."

Hilary — Fall River, Nova Scotia
"For the past few years I have successfully overwintered perennials in containers in our unheated garage, specifically a perennial Geranium, variegated ivy, and zebra grass. I usually wait until the end of October or early November, but before we get a really hard frost, water the plants lightly, trim them down then move them into the garage.

Come early April I bring them out, tidy them up, give them a little water and keep them close to the house for the first couple of weeks. By this time the Hosta and the Geranium have started sprouting new growth. The first year I just had one container, but now I have four and I'm wondering how a contained tree would work out!"

Rose Anne — Barrie, Ontario
"I garden in Zone 5 and I love growing perennials in containers. Many are drought tolerant and can survive my 3-week holiday in mid July! In the fall, usually late September, I simply take the perennials out of the container and plant them in my little east nursery at the side of my house. I set them in the lovely compost and in spring they are ready for replanting, in a container or in the garden. I make sure I take up lots of compost with the roots to give them a healthy soil base. Last year's top pick for outstanding performance was Agastache 'Blue Fortune'."

QUESTION: "Is mulch okay to use with all plants and flowers?" Tonya — Omer, Michigan

ANSWER: Basically, yes. Commercial bagged organic mulches such as ground bark or cocoa beans are the most common types used, and none of these are toxic or harmful to plants. Certain plants with succulent or fleshy leaves (like cactus or creeping Sedums) don't like moisture around their bases and stems, so if you mulch around these then gravel or stone would be a better choice.

The most important step when mulching perennials, annuals or shrubs is to avoid having deep mulch touching the plant stems. Mulch should always taper down to nothing immediately around the crown of the plant, where the stems grow. Many people make the mistake of piling mulch right around the stems. It's a no-no that can easily lead to rotting. One last thing to mention is mulch depth. Around perennials, aim for a depth of about 2 inches, which will help reduce weed seed germination and retain soil moisture. Any deeper is too much.

QUESTION: "I have several Sedum plants that grow very tall and lanky with spaces between the leaves and very few flower buds in the autumn. They are in full sun with extremely rich earth. They become so tall and spindly that they flop over and cannot support their own weight. If I pinch them back will it cause them to be fuller and produce more blossoms?" Kate — Toronto, Ontario

ANSWER: Absolutely try pinching them! You might be able to get away with two pinchings. And by "pinching" I really mean pruning. Prune them between now and early June by cutting them back by half. You can try a second pinch no later than early July, that time cutting the new growth since the first pinch back by half. The plants will be much bushier and more rounded and compact, the flower buds smaller and more self-supporting but still giving plenty of colour.

This month we will DRAW for three winners, and each will receive a signed copy of the Perennial Gardening Guide. Winners will be announced in the June newsletter, along with a sampling of your experiences.

Our best-selling book, the Perennial Gardening Guide (4th edition, March 2003) is a handy reference used by gardeners across North America — written by John Valleau, horticulturist for Heritage Perennials®. Available at your local Heritage Perennials® Dealer.