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Planting and Transplanting: Rhododendrons

Rhododendrons should never be planted in a location where the soil around the roots will dry out. They should be sheltered from the morning sun and also from extreme exposures of wind. During most of the growing season the falling of the dew as a result of the condensation of the moisture in the atmosphere causes little globules of water to remain on the surface of the leaves during the night. These particles of moisture are slowly evaporated during the early part of the morning. The rays of the early morning sun coming in direct contact with the leaves of rhododendrons on which these particles of moisture are still present are concentrated and focused by these many little "lenses" and cause a burning of the surface of the leaves which in the case of rhododendrons is extremely injurious to the plant. This is one of the most important reasons why rhododendrons with their sensitive leaf surface should not be exposed to the direct rays of the early morning sun, at least until after the heat of the day has caused an evaporation of the particles of moisture remaining on the leaves from the previous night. The baking out of the soil around the roots is extremely injurious to them. If this soil can be maintained at an even, cool temperature, their normal growth is better assured during the summer. They are not so much injured because of the cold, but because of the intense sun which causes evaporation of moisture from the leaves at a time when the ground is frozen and at a time when the plants are unable to replace this loss of moisture by additional water taken through the roots from the soil. This condition is especially true in the clay loam soils of the middle west.

They should never be watered with any water which contains lime. This is equally as important as the necessity of not planting rhododendrons in a limestone soil. It matters not how much the soil may be changed in the beds or how much leaf mold may be put in the beds in which to plant rhododendrons if the water with which they are frequently soaked comes from a limestone region.

Rhododendrons will grow in any good garden soil, but they much prefer a soil with a good deal of humus in it, and they should be thoroughly mulched with leaf mold soil which should never be cultivated, but left in its native woodland condition.

TRANSPLANTING ANNUALS. It is preferable to transplant annuals in a fine, loose loam, and never to transplant them in a heavier clay soil, which will pack and dry out. Upon the size of the plants will depend the care that it is necessary to give them immediately after transplanting. The smaller the plants the more care will be required in careful watering and shading during the hot portions of the day. While with proper care annuals may be transplanted at any season during the spring or early summer, yet the late spring (May through June 15th) is preferred. Annuals will develop best outdoors if they are transplanted at least two weeks in advance of the hot summer months. Frequent shifting, in pots or flats, is very beneficial through promoting the growth of fibrous roots which make transplanting more successful.