Ooops and Hardiness???


Ooops! I forgot to mention in the column on watering that it is very important plants go into winter well-watered. This means watering well into November in some years. Evergreeens, in particular, need to store moisture so that, when the ground freezes their roots, they can survive winter. Anti-dessicants, such as Wilt Pruf, applied prior to winter can also help retain moisture. Without adequate watering during the growing season, plants that seem o.k. may be so stressed they cannot survive. Do not let a few rainfalls lull you into thinking you are off the hook. Years, such as the last three out of four, have been so dry that many mature trees are dying. Water, water, water!!!!!

Plant hardiness and the hardiness zones are the focus of this article. The basics are quite simple, yet, there are so many exceptions and special circumstances, it can seem confusing. Hardiness zones are based on how hot and cold it gets in different regions of the country. Most of Maine falls into zones 3,4, and 5. Along the coast it is generally zone 5, meaning warmer in the winter than the interior mid-state or the mountains. Yet, within the 16 acres of Shaker Hill Nursery, there are places where snow piles high early and stays late. Winds do not reach these spots with much force. Zone 5 plants will survive in these pockets, yet zone 4 plants are what needs to be planted on the majority of the acreage. Microclimates on individual properties or regions allow the gardener to experiment. However, if you wish to play it safe, zone 4 or more cold tolerant plants are best.

An individual species, such as Swamp Maple (Acer rubrum), may be considered a zone 3b-9 tree, certainly acceptable for Maine. However, if the seed source or plant was from Tennessee, as an example, it may likely fall victim to late spring frosts or early fall freezeups. You should make sure your sources for plants have Maine-hardy stock and guarantee their product.

Early in my venture into growing field plants, Compact Burning Bush (Euonymus alatus "Compacta") were planted. Many had reached 5' when we had a dry summer followed by a winter where temperatures dropped to minus 20 degrees. The following spring, many had died or died back to the ground. Here is an example of a borderline plant that could survive many winters beyond a guarantee, yet not be right for you.

Most gardeners and nurserypersons push the limits with zone 5 plants. If you are willing to suffer setbacks to achieve a more unique landscape with borderline plants, it can be very rewarding. Generally, watering faithfully the first few seasons, choosing a more sheltered location, and some luck with a few mild winters until roots are established will help in achieving good results. Research your plants, talk to many people who have had success with the plant of your choice, and good luck.


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Poland Spring, Maine
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