Master gardener: What is the difference between summer raspberries and fall raspberries? Will fall raspberries grow here?
Raspberries have perennial roots and crowns, but their canes live for only two summers. Most raspberries are summer-bearing varieties. During the first year, the new green cane (primocane) grows leaves then develops a brown bark and is dormant in winter. In the second growing season the cane is called a floricane that produces fruit and then dies. New primocanes are produced each year, so fruit production continues year after year.
Ever-bearing raspberries, also called “fall-bearing” or “primocane-fruiting” raspberries, are able to flower during the first year. They produce fruit at the tips of the primocanes. During the second year, they can produce a summer crop on the same canes. One problem with this type of raspberry in Minnesota is that in areas of the state where the growing season is short, many fruits may be lost to early freezes. Pruning of fall-bearers may be adjusted to allow for both a fall and following summer crop, or to take just the fall crop.
Fall-bearing raspberry cultivars that produce early in the fall and should do well here are Autumn Bliss, Autumn Britten, Redwing and Polana.
Master gardener: When should I divide my perennials? My flower beds are overcrowded
Early fall is a good time to divide most perennials. Using a sharp spade, dig a circle around the clump, being as careful as you can to avoid damage to the roots. Then break the clump apart. Some will separate easily using only your gloved hands. Others will be so dense that you will need to use a knife or spade to separate them. With some you will need to slice right through the roots. Try not to disturb the dirt clinging to the roots, which may be difficult, but plants are amazingly resilient and, given plenty of water as fall progresses, will recover well.
Dig a hole about twice as wide as a newly divided clump and re-place the clump at its same growing level. Fill the hole with compost (and maybe some peat moss) and tamp it in firmly but not harshly. Water well at planting and at least weekly until the ground freezes. Plants also will benefit from 3-4 inches of mulch such as wood chips, straw or pine needles. If you have more divided clumps than you need, pot them up and give them away.
Master gardener: I would like to plant some bulbs for spring and early summer bloom. Which ones do you recommend for our area, and which bulbs should I plant this fall?
The bulbs that will be discussed are in the hardy bulb classification, which means their growth cycle needs a cold period (winter) to break their dormancy and begin spring flower development. Therefore, these bulbs are planted in the fall.
When you purchase your bulbs, check for any signs of damage or disease. The bulb should be firm and have a papery skin. Reject any bulb that is soft or shows signs of damage. It is best practice to plant your bulbs as soon as possible after purchasing them. In Minnesota planting time is usually from mid-September to mid-October to give the bulb some time to grow roots before the ground freezes. Tulips, however, can be planted as late as you can get them into the soil.
When choosing a location to plant bulbs, try a spot where they will receive enough light. The more light they receive, the better they come back each year. It is important to plant bulbs in well-drained soil. You will want to add some fertilizer, 5-10-10, at the time of planting, mixing it well with the existing soil. The planting depth and spacing depends on the individual bulb, but as a general rule, they are planted two-and-a-half times deeper than their diameter. In sandy soils, which we tend to have up here, plant them one or two inches deeper.
Place the bulb pointed end up, cover with soil and water thoroughly. Mulch the area with chopped leaves, grass clippings or straw to insulate the bulbs and keep the temperatures more constant during the fluctuations of fall and spring. From a design perspective, it usually looks better to plant bulbs in odd-numbered groups.
Early season flowering bulbs hardy for this area include chionodoxa (Glory of Snow), crocus, galanthus (Snowdrops), muscari, puschkinia and early tulips. Mid-season flowering bulbs include daffodil, Fritillaria imperialis and mid-season tulips. Late season flowering bulbs include Allium giganteum, Scilla sibirica (Siberian squill) and late tulips. Though gardeners enjoy tulips, deer do, too!
Readers: An excellent question was posed by a reader regarding last month’s column on rhubarb. The reader heard that the poison moves from the leaves of a rhubarb plant into the stalk by the fall.
According to information from the University of Minnesota and Iowa State University, some people mistakenly believe that rhubarb stalks are poisonous in the summer. The stalks grow “woodier” and tougher as they age, but they do not turn poisonous. If your rhubarb plants are healthy, you can pick a few stalks in the summer, without harming the plant, but it is not a good idea to do it very often because it will reduce the yield and quality of your rhubarb crop next year. Plant vigor is the reason you should not harvest rhubarb in the summer. Energy is gathered by the large leaves to be stored for next year’s growth.
The leaves are always poisonous. Although rhubarb leaves contain oxalic acid, which is poisonous, they can be placed in the compost pile. Like other organic acids, oxalic acid is not readily absorbed by plant roots. Compost containing decomposed rhubarb leaves can even be safely applied to the vegetable garden.
CROW WING COUNTY MASTER GARDENERS are trained and certified volunteers for the University of Minnesota Extension Service. All information given in this column is based on research and information provided by the University. To ask a question, call the Master Gardener Help Line at 218-824-1000, extension 4040, and leave a recorded message. A master gardener will return your call.
