Don't Kill Plants with Kindness

Too much care can kill plants as easily as too little care. The gardener who cares too much for his or her plants will more often overdo watering than any other gardening practice. Proper watering at planting and after planting is important, but improper watering can kill. Plants should be watered at planting time with enough water to settle the soil. Soil should not be packed or tamped after the water has been added.

Frequency of watering depends on the weather, so no definite schedule can be worked out in most cases. Generally, water often enough so plants do not wilt, but allow enough time between waterings so the soil dries well on the surface. If a plant is seen to wilt, water promptly. However, a plant that wilts while the soil is still wet has had extensive root damage, either from transplanting, overwatering or both. It should not be watered again until the soil has become drier. A plant that wilts in wet soil has much less chance of recovery than one that wilts temporarily because of dry soil.

Water conditions in heavy clay soils are much more difficult to evaluate than water conditions in sandy soils where drainage is good. If a hard pan exists beneath clay soils, carefully watering is even more critical because water cannot move out easily. Standing water in planting holes can sour and exclude air. Both conditions lead to root destruction. The new plant does not need a heavy diet of plant food to get established. Neither is fertilizer a medicine that cures the root damage done in the normal transplanting process. Fertilizer is important and beneficial when used properly, but can be damaging if applied excessively.

Plants can also be damaged by excessively high additions of manure, especially fresh manure, or dehydrated manures that are fairly high in nitrogen. Root damage caused by high fertilizer levels usually shows up next year in the leaves as curl, yellowing, scorch or premature drop. If conditions are severe, plants react in the same way they respond to too much water: permanent wilting, dieback and death. When in doubt, do not add fertilizer at planting time, and begin fertilization after plants become established and start normal shoot growth.

A little fertilizer can be beneficial at planting, and experienced gardeners usually add a little. Compost or other organic matter low in fertility, as well as superphosphate or bone meal may also be added at planting time. Some gardeners tend to place plants too deep in the soil, feeling that this gives the plants better stability and roots can get moisture better in dry weather. Deep planting can be dangerous, and woody plants should never be placed deeper than they were growing in the container or in the nursery.

Soil around the tender bark on the young tree trunk or shrub branches can cause bark deterioration, allowing diseases to enter and gradually girdle the stem or trunk. Many needled evergreens, as well as azaleas, rhododendrons and dogwoods are particularly sensitive to deep planting. Plant a little high to allow for settling so that the final position of the plant will never be too low.

Pest control is sometimes necessary for new plants. Always check labels to make sure that the plants will not be damaged by the pesticide used. Avoid spraying in extremely hot weather. A young plant needs all its leaves, and should not be subjected to any practice that reduces its functional leaf area.

http://www.ag.ndsu.edu/pubs/plantsci/landscap/pp744w.htm