By Rachel Vogan
Right now and for the next few months it is the best time to plant Rhododendrons.
Handy Hints To Guarantee Success and Healthy Growth. Always select well-grown plants in containers not less than 15cm across. When removing the pot check that the plants are not root bound, i.e.: if the plant has been in the container too long the roots will have become a tight interwoven solid mat. If this is the case it is very important to make cuts down at least four sides of the root ball. A small home fork or a wonder weeder is also good for this job. If the root ball is not matted, gently free the outside roots with your fingers before planting.
Preparation of the Hole Dig a hole at least twice the size of the root ball freeing up the surrounding soil and loosening the soil in the bottom to ensure good drainage. Good free drainage is imperative to growing healthy Rhododendrons. If your soil is not free draining in other words heavy and sticky, then add a generous quantity of fine bark, sand or compost and plant mounded up, with the top of the root at least 10cm above the soil level. In normal conditions where the soil is free draining, plant the top of the root ball at soil level. – Do not plant any deeper as this is sure to result in killing your new prized Rhododendron. Even when surprisingly close to the soil surface. After planting, press down firmly with your hands. Don't stamp heavily around the plant with your feet as this can damage the delicate roots and can prevent the necessary air movement to the roots as healthy roots means a healthy plant.
Watering I always water in with Trichoflow which contain beneficial fungus promoting growth and vigor. This will also reduce the chances of root rot infection. Assuming you have already established your soil is acid, i.e. skimpy on fertiliser. If any of your Rhododendrons start yellowing in the leaves I find the most effective remedy is to sprinkle a hand full of Epsom salts around the plant and water it in. After planting it is important to cover the area with the minim of organic mulch e.g. bark, pine needles or pea straw. These improve water balance in the soil, minimising water retention capacity and allowing steady moisture flow to the roots. Be cautious of increasing the water retention of heavy soils without providing extra drainage. As organic mulches decompose they improve drainage and growing conditions of the soil and also add humus, this an added bonus in the suppression of weed growth.
Foliage, Form and Flower Colours Rhododendron foliage’s and form are so diverse there is certainly a suitable plant for any specific location, town or country garden. Recent breeding has produced smaller, more compact plants for town gardens and containers.
Where to grow Rhododendrons prefer dappled shade however many of the small leafed varieties will tolerate full sun provided the roots are kept moist throughout summer. Plants in the sun do flower more prolifically than those in shade.
Pests and Diseases In cooler climates rhododendrons are untroubled by pests and diseases. Where thrips and powdery mildew are evident, spray the underside of the leaf.
Mulching Rhododendrons in their native environment enjoy wet summers and dry cold winters. Therefore it is important to keep well watered during dry summer periods. It is more beneficial for the plant to have a weekly soaking rather than a more regular light sprinkling. Bark mulch, pine needles or pea straw keep the roots cool and help to retain moisture. Brown edges on leaves indicate stress caused by a lack of water.
Below are some very good rhodos to look out for: