Feeding and mulching

FEEDING:

Just like us, Rhododendrons do need plenty of water and food! So many people forget to fertilize their plants and this is particularly important in the first years whilst they are getting themselves established. It is also essential if you are growing your plant in a pot.

A good slow release Rhododendron fertilizer, applied annually in March is recommended to feed the plant all season. If your plant is not flowering, then you could also apply Potash and Superphosphate in the summer to encourage flower buds. Superphosphate is useful to apply if planting in the autumn (the best time) as it encourages strong root growth. Remember that if you feed your plants too late in the summer, then this will encourage leaf growth at the expense of flowers next season! This new soft growth is then vunerable to early autumn frosts.

The main feeder roots of a Rhododendron are near the soil surface and are at the edge of the rootball. For this reason, when you are planting your Rhododendron there is no point in putting fertilizer into the bottom of the hole. We recommend that you sprinkle the slow release fertilizer around the top of the plant, avoiding the stem, and gently hoe into the soil. A good drink at this point is helpful.

Chlorotic leaves (where the leaves turn yellow with the veins remaining green) are often a sign of lack of iron. Iron sequestrene can be used in this situation. However, if you are regularly feeding your plants, it is unlikely that you would need this, and it is a relatively expensive fertilizer. Chlorosis of the leaf can also be caused by poor conditions such as drainage problems, soil pH or drought, so check these first.

Do not be tempted to over-fertilize. A symptom of this would be leaf tip burn where the edge of the leaf goes dry and brown. Some dwarf varieties and many species are particularly susceptible to over-feeding.

Please do avoid chicken and farmyard manures as they are too high in nitrogen for Rhododendrons and they will cause leaf burn. Similarly, also avoid bonemeal because it is too high in calcium.

MULCHING:

Your Rhododendrons will really love a good mulch and it has the added benefit of making your garden look attractive whilst helping your plants.

We do not recommend weed suppressing fabrics or matting. As mentioned above, Rhododendron are shallow rooted plants and these products interfere with soil aeration and drainage.

Avoid mulching around the stem. The best time to apply a mulch is in the autumn to help suppress weeds and retain moisture. But you can apply at any time, just ensure that the ground is moist before adding your mulch. We recommend that you apply a mulch of around 3cm.

What to use? As mentioned above, we would not recommend farmyard manures (too much nitrogen) or mushroom compost (too much lime). The ideal mulch would be either well rotted garden compost, pine needles or bark chippings (or a mix of any of these).