Dear Helen: As a transplanted Albertan, I am wondering what to do with some of the plants in my small townhouse garden. Glads, lilies and a dahlia that I planted need to be moved to a sunnier spot. When do I do this?
I planted rhubarb in the spring, too. Should I trim the stalks back now?
V.B.
Dear V.B.: Leave the rhubarb plant to die back naturally. Then, pull away the withered top growth.
When new shoots begin nosing through the ground in spring, lay a nourishing mulch of compost around them. Do this again, after watering deeply, as the weather warms in June and as harvesting winds down. Harvest sparingly in the plant's second year. Leave at least two-thirds of the stalks on the plant at each gathering.
Gladiolus corms often keep well in the ground in our climate, if the soil is light and well drained. If you wish to chance storing them in-ground, leave the foliage intact as long as it remains in good condition. Cut the tops off after frost has damaged them.
If you choose to lift the corms for storing and replanting in the spring, dig the plants after the first light frost. Cut off the tops right away, close to the new corms. Set the harvested corms single-layered in a warm (26 C), airy place to cure for two or three weeks. Then twist the old, spent corms away from the bottom of the new one and allow another week of airing in warmth.
Store the corms in open trays, bags or shallow boxes, uncovered, in a dry, dark, cool spot, ideally in the 5 to 10 C range.
Lilies. Move lilies in the fall, after the foliage has browned. Cut the stalks off at soil level first. Replant immediately in well-drained soil replenished with compost and fertilizer. The depth of soil over the bulbs should be 12 to 15 centimetres or 10 to 12.5 cm for smaller Asiatic lily bulbs.
Stem-rooting lilies with large bulbs, such as the Trumpets, may be covered with up to 25 cm of soil.
Dahlia. Unless the soil is wet and/or hosting suspicious numbers of wireworms, the dahlia will likely overwinter well in its site. Clear away frost-blackened foliage and lay a light covering of soil over the clump. Mark it. Dig it up in the spring, divide it if necessary, and replant.
If you chose to lift and store the clump, do this when top growth dies back. Let the tuberous roots dry a little, and brush off clinging soil. Recut the stem, just above where the roots join it, leaving the stem base intact.
Store the dahlia clump, covered with vermiculite or sawdust, in an open, plastic-lined box placed in a dark, cool spot at around 6 C. Check the roots periodically for shrivelling, which indicates the need for a spray-misting with water to lightly moisten the storage medium.
