The Rhododendron is a flowering shrub whose foliage East persistent. His abundant flowers with multiple shapes and colors depending on the variety are grouped together in spectacular inflorescences contrasting beautifully with the dark green of the leaves. Depending on its variety, this large shrub reaches between 3 and 5 meters in height. It can be used alone, in groups, on a lawn, in a rock garden, associated or not with other shrubs of heather soil and can also be cultivated in large vats. Let’s see where and how to plant a Rhododendron, what its maintenance needs are and take a look at its amazing flowering.
Plant a Rhododendron
The Rhododendron appreciates semi-shaded exhibitions but its foot must be able to be sufficiently sunny. It can acclimatize in an area exposed to direct sunlight only if the earth is sufficiently moist. He likes them heather-type acid soils whose Hydrogen potential (pH) is 4 to 6, humus-bearing, fresh but perfectly drained because stagnant water is highly detrimental to it. Rhododendron does not tolerate drafts, nor calcareous earth because it is too compact, and fear the scorching sun. Respecting all these conditions is essential to guarantee the recovery and then the blossoming of this beautiful flowering shrub.
Planting Rhododendron can be done in the month ofOctober or during the spring, always outside the frost period. It requires that the following points be observed.
- Start by soaking the root ball by soaking it in water for about twenty minutes.
- Dig a hole at least 40 cm deep and 100 cm in diameter because the roots tend to develop horizontally.
- Remove stones, plant debris, roots of weeds.
- Place the shrub in the center.
- Fill the planting hole with a mixture of 20% compost, 30% non-calcareous topsoil or flowering shrub soil and 50% heather soil. Note that you can incorporate a little sand into the mixture to promote drainage.
- Firmly press down with your foot.
- Water copiously.
We recommend to mulch the ground at the foot of the Rhododendron to retain freshness. A pine bark mulch quite suitable. On the one hand, by decomposing over time, this type of mulch enriches the soil with nutrients, on the other hand it brings acidity to the soil. The mulch also protects the roots of the shrub against severe frost.
Caring for a Rhododendron
Easy to grow, the Rhododendron is the pride of gardeners. It is not very demanding, but it should not be neglected.
During the two years following the planting of Rhododendron, it is essential to ensure water frequently so that the earth is always moist. The roots should not, however, soak in stagnant water, hence the importance of ensuring that this shrub has a well-drained land and not calcareous. Watering a Rhododendron in pot should be done as soon as the substrate surface is dry.
The Rhododendron in winter
This remarkably floriferous shrub displays a beautiful rusticity. It therefore supports temperatures well from -15 to -20 ° C, and some varieties can even tolerate down to -30 ° C! Be careful, however, if it is grown in a pot. Better to place it away from strong frost, if only to prevent the container from bursting. A wintering veil is very useful in this case.
Diseases and parasites
It is not very sensitive to diseases and parasites as long as he enjoys an appropriate situation and his foot does not bathe in stagnant water. Too much humidity can cause browning of buds.
Limestone is responsible for the ferric chlorosis spotted at yellowing of leaves. Applying heather soil to the surface along with a regular addition of heather plant food is usually sufficient to eliminate the problem.
This shrub can sometimes be the prey of the fungus Exobasidium vaccinii responsible for leaf gall. There are then growths on some leaves that just need to be removed to overcome this disease.
On the other hand, the Phytophthora cinamommi is a dreadful mushroom for the Rhododendron since it generally causes the total dieback of the shrub cannot survive there. Only the use of a fungicide can be effective if it occurs early enough. But it is not easy to act early because the signs appear when the damage is already done.
So that the Rhododendron retains its beautiful appearance, the faded flowers are removed as they go. Otherwise, pruning is limited to removing dead wood. Can also promote branching by reducing the branches in early October. To do this, it is necessary to prune just above one eye.
Flowering lasts for about three months. It is interesting to grow different varieties to enjoy a staggered flowering because, depending on the case, some flower as early as March, others until autumn. All are covered with sumptuous terminal inflorescences, composed of large flowers, sometimes up to 25 cm in diameter, in various colors, white, red, purple, pink, yellow, and even variegated or striped … splendid shades.
It is interesting to associate it with other plants and heather shrubs such as Hydrangea, Japanese Maple or even Azalea, the latter also being a Rhododendron. For information, in horticulture we generally call Azaleas (from China or mollis) or even deciduous Rhododendrons the varieties with deciduous foliage and Rhododendrons or Japanese Azaleas, those with evergreen foliage even if all these shrubs and plants belong to the same botanical genus.