Spring flowering bulbs add beauty to any landscape. In Minnesota the best time to plant is from mid-September through mid-October. Tulips can be planted until the soil begins to freeze.
When choosing bulbs make sure they are hardy for our area. Bulbs listed as hardy in zone 3 or 4 should survive. Bulbs are graded and priced accordingly based on bulb circumference. Always select the largest circumference bulbs to ensure stronger and larger flowers. Pick bulbs that are firm with crisp papery skins. A little mold on the skin of the bulb is not a concern as long as the bulb itself is free of mold. Check the root plate for any chips or scars which could result in poor root growth.
Bulbs should be planted in a location that receives six to eight hours of full sunlight per day and is free of standing water. Heavily shaded locations, low areas, or locations near downspouts should be avoided. In a shaded yard it may seem difficult to find an area that will receive enough sunlight. Remember that most spring bulbs bloom before trees leaf out and as long as the foliage receives six weeks of good sunlight they should bloom the following year.
Before planting call Gopher State One Call so buried utilities can be located. Dig or till soil to a depth of 10 inches. This is a perfect time to incorporate organic matter such as peat moss, compost, or shredded leaf mulch. As you are working the soil add two to three pounds of a 5-10-10 fertilizer per 100 square feet. Follow the guidelines that came with the bulbs for proper planting depth and spacing. If guidelines are not available, a good rule of thumb is to plant the bulb two and one half times its height with depth being measured from the top of the bulb.
After planting, water bulbs thoroughly. Mulch the surface with three to five inches of leaf material, grass clippings, hay, or straw. Mulch will insulate the bulbs and help keep the soil temperature more constant during late fall and early spring.
Rake back the mulch in spring as the shoots begin to emerge, but keep a little handy in case of hard frosts that may damage early emerging shoots. Proper post bloom care is necessary to allow plants to store food in the bulb to ensure good flowering next season. Deadhead plants after blooming by cutting the flower stalks as close to the leaves as possible. Fertilize lightly using a handful of 5-10-10 fertilizer or a bulb fertilizer as the flowers begin to decline. Do not cut leaves back until they are completely yellow or have started to dry. As longs as the leaves are green, they continue to feed the bulb.
If you have questions about bulbs please call me at the University of Minnesota Extension office, Clay County at 218-299-5020, 1-800-299-5020 or email me at nels1657@umn.edu. Check out our website at www.extension.umn.edu/county/clay/