April 12, 2007 at 7:42 a.m.
One of our most popular plants this year is blueberries. Many of the spring classes we are sponsoring are related to the plants we are selling. Saturday, May 5, Diane Patras, Chisago County Master Gardener, will have a class on raising blueberries. The second class of the morning will feature Al and Judy Olson, owners of Wild Mountain Vineyard in Taylors Falls, presenting a class on growing grapes.
Blueberries grow best in a sunny location. Plants will tolerate partial shade, but as shade increases, plants produce fewer blossom and fruit production declines. Some gardeners remember going with their parents or grandparents up north to pick blueberries. There is a misconception that because they picked blueberries in the woods, that they like shade. They forget that the berries were found in the open areas of the woods. Avoid areas surrounded by trees, which provide too much shade, compete with plants for water and nutrients, and interfere with air movement around plants. Poor air movement increases danger of spring frost injury to blossoms and favors diseases development.
Blueberry plants grow best in acid soils (ph 4.0 to 5.0) that are well-drained, loose, and high in organic matter. Several years ago I was given blueberries plants for fathers day. I planted them in a sunny area, but they began a slow death and within two years they were gone. Several gardeners told me that their blueberries had a similar fate.
So, I checked with Rod Elmstrand, who at that time was the Chisago County Extension Educator. Rod suggested I have the soil tested and the ph tested out at 7.5, which is way too high for blueberries.
Blueberries are in the health family, which includes azaleas, rhododendrons, and cranberries. They are tolerant of acid soil and have low fertility requirements. When heath family plants are grown on alkaline soil near foundations of homes (where lime leaches onto the soil raising the ph) iron deficiency can become apparent. When soil becomes more acidic (lower ph), iron is more easily dissolved and absorbed.
The planting directions may be different for you because your soil may be friendlier for raising blueberries. Sandy soils tend to have a lower ph that the heavy clay-loam I have. I had to dig holes about 18 inches deep and about six feet apart. The reason for this is because the plants will turn into bushes about three feet high.
Next, I mixed the soil I had dug out with acid peat (moss) in about a 1 to 1 ratio. You can also mix about 1/2 cup elemental sulfur in the peat/soil mixture before planting the bush. The purpose for using elemental sulfur is to help lower the ph. Be sure not to use aluminum sulfate as this compound can be toxic to the root and even kill the plant.
One of the sure things by ordering from us is that all our plants are for our area. It seems as though every business is selling plants of some kind. You can't always go by the labels as they are not always for our zone. The three varieties of blueberries we sell a Chippewa, Northland, and Northblue.
Chippewa is a mid-season plant that is compact, upright, and grows about four feet high. The fruit is medium large, very light blue, firm and very sweet. Chippewa is recommended in all areas where a super cold hardy variety is desired.
North blue is a mid-season variety. It's a semi-dwarf bush, growing to a height, of three to four feet. The fruit is large, dark blue, with a wild blueberry flavor. Northblue is quite productive for its size, producing between three to seven pounds per bush.
Northland is an early variety that is vigorous, spreading, with medium blue berries, medium size, and very sweet.
It is a good idea to plant more than one variety of blueberries and to alternate them in the same row. This is because some varieties will have better production if they are able to cross-pollinate.
We still have a limited number of plants available to order. Due to the office hours at the Extension Office in North Branch being reduced, some requests for information may be delayed. Therefore, I do not mind if you call me at my home regarding plant orders or class offerings. My number is 651-257-4496.
Our spring class series 'Garden Fever' has begun! The next classes on Saturday April 21 will cover Managing Fruit Tree Pests and Raising Strawberries and Raspberries. Class brochures as well as the plant order forms are available on the website at www.extension.umn.edu/county/chisago or you can call the Extension office at 651-674-4417 to have one mailed to you.
Cutback in staffing has made it necessary for the Extension Office to limit hours of operation. At present, the office will be open on Tuesdays and Thursdays. We would suggest that you call ahead to verify that the office is open before you stop by.