Making Your Mulch Fit the Plant

Making Your Mulch Fit the Plant :

Remember: the purpose of mulching is to keep the ground frozen, not to keep the plants warm.

Autumn is a great time to enjoy the last weeks of gardening, however many people "jump the gun" by putting their plants to bed too soon. With the exception of water plants, you do not need to mulch for the winter until winter is almost upon us! Remember: the purpose of mulching is to keep the ground frozen, not to keep the plants warm. In late October or early November (depending upon the weather) cut back most perennials to an inch or two above the ground except for a few that contrast nicely against the snow. Once the ground has frozen—in late November or early December—you can assemble your mulching materials. Different plants require different kinds of winter protection, and these are described below.

Perennials: You should mulch everything if you are not prepared to take the consequences of losing a few plants each winter. Otherwise, mulch plants that have been planted within the last year or two, and those that are tender in our area. Six to eight inches of marsh hay or straw, or even pine bows cut from discarded Christmas trees, provide better protection than leaves which can mat together and smother emerging plants in the spring.

Roses: If you have hardy shrub roses, you can usually get by without mulching at all. All others should be protected. If you have doubts about what kind of rose you have, protect it. We do not recommend rose cones which tend to heat up inside during thaw periods, temporarily "defrosting" the rose. This defeats the purpose of mulching. A better solution is the rose collar, used to hold 10-12 inches of soil that have been mounded over the crown of the rose in mid to late October. Once the mound has frozen, add a layer of straw to keep the soil frozen until spring. While exposed canes may die back during the winter, the critical point where the rose has been grafte is well protected.

Climbing roses are treated differently in that you must protect the canes as well as the crown of the plant. This is because climbers usually bloom on the previous season’s wood. The easiest method is to protect the standing canes by leaning discarded Christmas trees against them. If this seems awkward, you can construct a burlap "tube" with tall garden stakes used for support, and this can be stuffed with straw.

Chrysanthemums: The term "Hardy Mum" is almost a misnomer in Wisconsin, though you can improve the plant’s chances for survival by planting in May (not September which gives little time for the roots to become established before winter). Johannsen’s carries a good selection of "starter" mums in May. Regardless of when you plant them, all mums require winter protection. Mulch mums as you would a rose, with a good mound of top soil placed over the crown of the plant once it has died in late fall and been cut back to several inches. Once the mound freezes, cover it with straw or pine bows to keep it frozen through thaw periods. While no guarantee that your mums will survive a Wisconsin winter, this method of mulching works better than any other.

Water Plants: The safest method to protect water plants (unless you are among the few who have a very deep pond in which plants are rooted in the bottom) is to bring all plants—even those that are hardy—in for the winter. Plants may be left in the pond until nights are consistently cold—40 degrees or below. When such temperatures occur, bring plants in, wrap them in damp layers of

newspaper, and place these in plastic trash bags, folding the tops of the bags over loosely. Store the plants in a cool basement, checking them two or three times during the winter to make sure that the newspapers are still moist.