Experienced gardeners usually have no problem with growing rhododendrons, but for amateurs, their first attempts to maintain these beautiful shrubs often fail.Heather plants, which include rhododendrons, have specific, differentiated and quite different cultivation requirements from other groups of plants. How to meet them?
Under natural conditions, heather plants have adapted to growth in areas that are quite poor in nutrients, but with an acidic substrate, so they should be provided with a soil pH of 4-5.5. Most rhododendrons prefer substrates that are constantly moist, permeable and rich in organic matter.
The root system of rhododendrons is shallow and consists of numerous, very fine roots. These roots grow into the ground to a small depth, but they spread to the sides.Therefore, the hole dug for plants does not have to be deep (30 to 40 cm is enough), but it should be wide, at least 3-4 times wider than the root ball of the planted rhododendrons.
The excavated soil should be mixed with acid peat and composted pine bark, and only then should the plants be planted in the substrate prepared in this way. On alkaline soils, it is best to replace the soil dug up from below with a substrate for heather plants. Too heavy soils should be loosened with the addition of sand.
Before removing the plants from the pots, they need to be watered well.The easiest way is to put the plants with the containers in a vessel with water for 20-30 minutes.After draining the excess water and carefully removing the plants from the pots, if the lump is strongly felt and grown together, it can be slightly disturbed (score with a pruner) at the base.This will allow the rhododendrons to take root in the ground faster and take root.
When placing the plants in the pit, be careful not to damage the rather heavy root ball. Remember to never buy rhododendrons from the so-called bare root, i.e. without a dense root ball. Such rhododendrons won't catch on. Plants are planted at the same depth as they grew in containers or in the ground (in the case of ballot plants).The soil around the plants is lightly pressed with your hands and watered abundantly.
The surface of the soil around the plants should be mulched with a few centimeters of composted pine bark.This reduces water evaporation from the soil, reduces weed infestation and protects the root system against freezing.In addition, mulching with pine bark increases the content of organic matter in the soil and causes its acidification.
Until the plants take root well (i.e. for about 2 years), they should not be fertilized. Feeding immediately after planting and applying too high doses of fertilizers are one of the most common causes of dieback of rhododendrons.In the first years of cultivation, rhododendrons should be systematically watered to prevent the substrate from drying out. The shrubs grow well when the soil is constantly slightly moist, but once they are well established, the shorter dry spells pass without much damage.
Why are there brown spots on rhododendrons?
Mineral deficiencies (potassium, boron and phosphorus) are a common cause of irregular spots, yellowing of the tissues between the veins and browning of the leaf blade. Plant frosts and various fungal diseases, such as phytophthora, are also manifested by browning and leaf fall.
- explains the expert Anna Błaszczak
Best place to grow
Finding a suitable place for them is one of the important factors determining the success of growing rhododendrons.These plants do best in secluded, sheltered, partially shaded and constantly moist places, preferably near tall trees such as pines, firs or oaks.If we have a choice of a place at the back of the house, in front of and facing the street, choose the first one.
The cultivation of rhododendrons is favored by a specific microclimate created by coniferous trees and shrubs. These plants not only protect rhododendrons from the wind, but also emit phytoncides, and decomposing needles acidify the substrate, e.g. enriching the soil with humus.
