Minnesota perfect for perennials
Living in Minnesota has it advantages! We have an abundance of perennials which need a dormancy period that signals the end of one growing season. Then they need a long cold period, after which they burst forth with new foliage and flowers in the warmth of spring. If we lived in Florida, the Deep South, Texas, or Southern California, it is simply too hot, for too long, with too brief a cold period and mild a winter for most of our perennials to survive. The cold period is also a time for gardeners to recharge and set new goals and expectations for themselves, so we are ready to garden as soon as spring emerges. However now is a good time to evaluate and decide if some of those perennials need to be divided. One big advantage of dividing perennials in the fall is you know which plants have overgrown their territories, what colors they are, and how much you want to take out of the planting to keep it in control.
The day before you transplant it is a good idea to water the plant to be transplanted well. Also dig the hole where you are going to transplant the plant, Add compost, peat moss, well-rotted manure, or 10-10-10 fertilizer with the soil in the base of the hole, and water that well so the soil is damp before you move the plant. Before you dig with your spade, cut the foliage of the plant to be transplanted, down to the ground in the case of peonies, and to about four to six inches for most others. This is so the roots do not have to support foliage above ground while trying to establish roots in the new location. Spade around each plant, lifting it from each side and last try to spade under the root mass and lift carefully so that the least roots possible are broken. The following are a list of perennials which divide well now:
Bleeding heart: Divide as foliage goes dormant in heat. The roots of bleeding hearts are brittle, so handle carefully. Plant the same depth as the mother plant.
Columbine: Seedlings do not always look like parent plant so divide hybrids every few years to keep this short-lived perennial around.
Coral bells (Heuchera): Have a woody crown, you don't need to worry about getting roots with each piece. Coral bells sprout from the stem, cut individual leaves back by half. It is not necessary for the new growth, but you could use a rooting hormone to encourage growth of new roots.
Daylilies: To keep clumps healthy they should be divided every 5-7 years. If they are the type that re-bloom, they are best divided in the spring. Cut back leaves to 4-5 inches. Daylilies have fibrous or spreading roots. Pull these apart or cut through them with a sharp spade, but each division should have at least 2-3 stems or fans. To get bigger plants faster, divide the original plant in half or thirds.
Dianthus: These have a mat forming type of root system as they grow. To transplant cut a piece from the edge of the plant and replant it. In the spring there will be a mass of dead leaves from last year's growth, this is where the new plant will sprout, so be careful not to disturb these dead leaves. They may not look like it, but there is life in those dead leaves.
Iris: Should be divided every 3-4 years. Cut leaves above the ground back to 4 or 5 inches. The rhizomes are food storage units. Each rhizomes should have at least one fan of 3-4 leaves and a good cluster of roots. The hole should be shallow, with a ridge made in the center of the hole. Place the rhizomes on the ridge with the roots going down on either side of the ridge. Cover with one inch of soil, firm the soil, than water well.
Peonies: Are a plant that does not like to be transplanted, so unless you have a reason to move it and if it is doing well where it is, don't move it. However, if you need to transplant it cut the leaves and stems down to the ground. Dig around and under plant, and when you lift, take care not to break off roots or eyes. Wash off and cut pieces of root so each piece has 3-5 eyes. Plant with eyes or crown facing up and not more than 1 ½ -2 inches deep. If they are planted too deep they will not bloom, and more than 2 inches is too deep.
Asiatic and Oriental lilies: Because lilies have "contractile roots" which pull them deeper into the soil each year, you want to make sure the soil beneath the lilies is mixed well with added nutrients as mentioned earlier. Lilies should be cut down to 4-5 inches before digging. Each lily division should have 3-5 shoots with roots attached. Lilies should be planted 4-6 inches deep from the top of the bulb. The soil should be firmed and watered well.
Kyle Schulz is a Wadena County Master Gardener from Sebeka, and the regular gardening columnist for the Wadena Pioneer Journal.