Perennials - Winter Survival Guide for Your Garden
Find your zone with this map from the USDA map. Because Western America has such a wide range of climates, a more accurate map detailing 24 zones is found in the Sunset Western Garden Book. This takes into account factors other than just minimum temperature, such as desert winds, ocean influence, mountains and valleys...A snow cover over your garden can actually be a good thing. Just as an igloo protects those inside, the snow insulates the ground from extreme fluctuations in temperature, as well as from the effects of freezing winds. Though hidden from the eye, the crowns of these plants must be protected from trampling or other unknowing destruction. Just because the garden looks like a snowy expanse does not mean the kids can stab their ski poles all over. Rolling giant snowman parts over them can compact the soil (unless it is solidly frozen), and the semi-permanent nature of perennials makes it difficult to restore the compacted soil in the spring. There is always that choice plant that is just not cold-hardy for your area. The temptation is great to try it anyway. This either means gardening in a state of denial ("It probably will not get too cold this year." or "This plant is probably not as tender as years of experience has shown.") Some tender perennials such as cannas, tender bulbs, and others, depending on your climate, should have been lifted and stored till next spring. If you did not do this yet and your ground is not frozen, it may not be too late. If you don't know what I am talking about, this probably does not apply to you. Try lifting the whole clump with a fork. Do not try to separate the earth when it is hard (frozen or dry), as that can tear many roots when it comes apart. Store them in slightly moist peat moss or wood shavings. Air is essential to prevent fungus growth, so don't put them in closed plastic boxes. Too wet and they rot. The classic "unheated porch that never freezes" is a good place to keep these roots, if such a place really exists. A garage may be good, too, but be careful - if too warm the plants may begin to sprout prematurely, only to be cruelly cut down by a sudden cold spell or the growth may languish and die in the darkness with no light or moisture to nurture them. Remember, you only want them to rest quietly till spring. Once all threat of frost is over, plant your carefully tended treasure as though it were new, and enjoy the fruits of your labor.