Plant your Rhododendrons in spring or early fall. Because most varieties require filtered shade, avoid areas with deep shade or full hot sun when selecting your place to plant. A sunny spot that receives a few hours of shade is perfect.
Your soil should be well-drained, moist, and acidic (pH 4.5–6).
When planting, space plants 2’ to 6’ apart. Dig a hole as deep as the root ball and 2 times as wide.
Set your new plants so that their top roots are at soil level or slightly below. If you plant them any deeper, the roots may rot.
Fill the hole half full with soil, and amend with Aged Cow Manure. Water it well to settle the soil before filling with remainder of soil.
Rhododendrons have shallow root systems and need moist soil and mulch to keep them from drying out. Add mint compost as a top dressing after planting.
Mulch plants every spring with 2 to 5 inches of mulch or compost to protect shallow roots and retain soil moisture. A lack of water reduces flower-bud formation. Keep mulch a few inches away from the trunk to avoid trunk rot.
Fertilize rhododendrons sparingly and only when flower buds swell in the early spring, even if they are fall bloomers. Heavy applications of fertilizer will burn the plants. We recommend using Founder's Fish Fertilizer to avoid burn.
Water plants during the spring and summer if rainfall is less than 1 inch per week.
After flowering, deadhead where practical, to promote vegetative growth rather than seed production. Remove dead flowers from rhododendrons carefully as next year’s buds are just under the old flower heads.
In regions with severe winters, wrap evergreen rhododendrons with burlap in the fall.
Transplant rhododendrons whenever the ground is not frozen or waterlogged, preferably in fall.
In general, do not prune spring-flowering shrubs such as rhododendrons. If you need to reduce height, prune after flowering in the spring. Otherwise, just remove dead, damaged, or diseased branches anytime. On young and old plants, simply snap off spent flower stalks by bending them over until they break away from their stems. Be careful not to damage growth buds at the base of each flower stalk.