Hey there, time traveller!
This article was published 27/9/2013 (1272 days ago), so information in it may no longer be current.
The garden is almost done for the year and just when you thought you were safe and have finally planted all of the potted plants that have been languishing all summer on your driveway or patio, along comes fall and a whole new opportunity to replant, readjust, remove and add to the garden.
Lily bulbs may be planted in the spring, but the very best time to plant them is in the fall. Our Zone 2b-3 growing season is too short for oriental lilies to vernalize (i.e. undergo the necessary period of rest and cold temperatures in order to hasten plant development and flowering). They may make it through one winter, and perhaps if you are lucky, two winters, but that is probably the longest they will live.
Likewise, trumpet lilies are more tender than the Asiatic or martagons, but hybridizers are finally breeding hardier trumpets and they too will survive our winters. Oddly enough, although orientals and trumpets by themselves are marginally hardy, when crossed they become Orientpets and gain the hybrid vigour that permits them to not only survive, but thrive in our inhospitable climate.
When planting lilies, there is no distinction between the three groups noted above. They should all be planted between four and six inches (10 and 15 centimetres) below the soil level and then left strictly alone. Do not, under any circumstances, start working the garden in the spring with your garden tools where lilies have been planted, or you may be rewarded with a horrible popping sound, which means you have just beheaded a lily. The entire growing season is wasted as the flowers come from the tips of the lily stem. Of course, the lilies aren't that crazy about being beheaded either. My motto is "walk around the garden in the spring with your hands behind your back." Do not investigate, touch, dig or otherwise disturb the soil, and that goes for all perennials, not only lilies.
The lily beetle (Lilioceris lilii) is a little red beetle, very pretty and very, very destructive. I have heard of people digging out hundreds of lily bulbs from their gardens and disposing of them. That should definitely not happen! They do not live in the lily bulbs. The lily beetle only goes after the genus Lilium and some fritillarias, and they can be kept under control by closely monitoring the plants from the early spring onwards. Spraying the plants or picking off the beetles by hand is necessary. The Manitoba Regional Lily Society's website (www.manitobalilies.ca) has a dedicated page on the lily beetle, and although it is not permitted to recommend any particular product, some of us who do belong to the society have been using End-All double strength spray, which works quite nicely. We also hand-pick the beetles and dispose of them in various creative ways -- dropping them into kerosene, bleach, ammonia, squishing them between rocks, etc.
Peonies may be planted in spring, but fall is definitely the time to think about moving, transplanting or simply purchasing new ones. Bare root peonies are really small bulbous tubers with little pink or white "eyes" or shoots at the top, very much like dahlia roots. These eyes are very delicate and brittle, so care must be taken not to injure them or break them off. A peony tuber with no eyes will not grow. Likewise, the eyes must not be allowed to dry out. That being said, I have inadvertently left fern-leafed peonies lying in a plastic grocery bag on the driveway over winter, and the next spring there they were, pink eyes and all!
Peony roots should be planted so the eyes are no deeper than two inches (five cm) below the soil surface, or they will not flower. They will grow leaves, but no buds. Peonies may be planted right up until the soil is too hard to dig and will be perfectly happy to be planted in a mix of soil and snow.
Both Chinese and Japanese tree peonies are grafted onto a lactiflora rootstock and require a completely different planting method. The graft shows as a thickened part of the stem, and it is from here the eyes or stems sprout. Therefore, the entire plant, right up to the graft and beyond, must be buried below the soil level.
Optimally, this would require a hole to be dug much deeper than the lactiflora, so the eyes are protected. Even if planted deeper than the suggested two inches, the suffruticosa will flower. As well, it will develop its own roots. Caution must be taken not to let the lactiflora rootstock take over and send up its own shoots. You will be able to differentiate between the different types of leaves if this happens, in which case the offending shoots must be removed. So far I have never come across this happening in my own garden.
The fall is also the best time to plant the spring-flowering bulbs such as tulips, daffodils, scillas, pushkinias, crocuses and snowdrops. Most nurseries have nice selections right now, and plant catalogues offering bulbs for fall planting have been filling mailboxes for the last few weeks. I find that although I say I will not plant fall bulbs this year, I always succumb to the siren call of the beautiful pictures and descriptions.
The rule of thumb is fall is also the best time to transplant early summer-flowering perennials, such as peonies, irises, columbines, delphiniums, campanulas and anything that blooms in June or July (including hostas and ferns). Leave the fall blooming perennials such as chrysanthemums, fall asters and daisies, Joe Pye, echinacea and Monkshood alone. They may be transplanted in the early spring when they first emerge.
I now rest my case about fall being "safe," and must rush back out to the garden to finish planting those poor plants that have languished on my patio all summer.