Know Your Zone
When creating or revising your 2012 landscaping plan be sure to check out the new Plant Hardiness Zone Map recently released by The United States Department of Agriculture. The new map might not be the zone envy cure that many Minnesotans growers and landscapers long for – but most of the Twin Cities metro area saw at least a half zone increase (from 4a to 4b) and one South Minneapolis/Richfield pocket, called a micro-climate, is even classified as a 5. Other parts of the state saw as much as a whole zone shift.
We have to remember it is still Minnesota, and we are susceptible to all kinds of unusual weather patterns from one year to the next, but this new map should at least encourage some fun plant experimentation in 2012. Maybe there is a Japanese maple in your future?

This is the first change to the map since 1990 – and reflects a general warming trend across Minnesota for the past 30 years. The map is based on average annual minimum winter temperatures, and divided into 10-degree F zones. It is the standard way to predict which plants are most likely to grow and thrive in a particular area. Click here for interactive version of the map available at the USDA website, allowing you to search by zip code and zoom in on your own neighborhood.
Our Strange Winter
It’s been a strange winter in Minnesota this year. Conditions – like the fall drought, extreme temperature fluctuations, and light snow cover – are posing some unique gardening concerns. Julie Weisenhorn, master gardener with the University of Minnesota Extension School was recently on the Mid-Morning Show on Minnesota Public Radio to address these issues. You can hear the complete January 19 broadcast here.
In the meantime, here are some tidbits from the program:
Fall Drought and Severe Cold Temperatures: Minnesota started winter this year with a precipitation deficit. Unless we watered our evergreens, shrubs and plants well in the fall the drought may mean that their roots are not hydrated well enough. This plus the lack of an insulating snow cover may result in some winter die back.
Combined with the periods of severe cold, evergreens may be especially susceptible to winter burn. Some of the early spring blooming shrubs (i.e. magnolias, azaleas) may also see some winter damage on their buds and foliage. However, when spring arrives it is best to take a wait and see approach. Foliage damage does not necessarily mean permanent damage to the branch. It may still push out new growth and make a nice recovery in the spring.
Warm Winter: This is a welcome oxymoron to Minnesotans – but it is causing some alarm for gardeners who are seeing their bulbs and plants putting up green shoots much too early. Higher temperatures can kick plants out of their usual winter dormancy. The truth is no one knows if this is a temporary aberration or a death knell. Buds may die back and some foliage will display with black edges. However, the bulb, rhizome, or plant may recover in the spring and produce new buds and eventually its beloved blooms – and if not this season then perhaps the next. Hope springs eternal!
Light Snow Cover and Mulching: The lack of snow this year means that we do not have our usual frost insulator for the ground. Some of our more fragile plants may not survive this kind of winter.
Mulching though is a good remedy – and it is not too late consider doing some mulching now, especially for the more tender perennials. The purpose of mulching is to slowly put plants into dormancy in the fall and then slowly bring them out of dormancy in the spring. It may be too late given the bitter cold we had earlier – but mulching now may still help with that critical emergent time – keeping plants from putting out shoots too early or offering protection to new growth against sudden, last minute cold snaps. If you still have bags of leaves from last fall that makes great mulch. Some nurseries may still have straw available.
Amazing mulching fact: Mark Seeley, University of Minnesota climatologist, noted that in their testing unprotected winter soil temperatures dropped as much as 41°. But in mulched areas the soil temperature dropped only 8°. Mulching works!
In the spring be cautious about removing mulch. As plants starts to grow, gently pull away mulch from the base of the plant but mound it up nearby in case you want to recover for the inevitable Minnesota cold snap, winter’s last hurrah.
Go Native: Next year consider planting more Minnesota native plants, trees and shrubs as they have already adapted to our odd weather patterns. But bear in mind the new zone map – our warming climate is bringing new native plants into our area and some are not as well suited as they once were. If you have questions, ask Tom.





















































































