How to plant, grow and care for rhododendrons (2024)

FAQs

How do you plant and care for rhododendrons? ›

Shrubs need six hours of sun daily. If you live in the warmer end of their growing zones, be sure you choose a site that gets afternoon shade. Soil should be well-drained, moist, and acidic (pH 4.5 to 6). Rhododendrons don't do well in heavy soils that drain poorly.

Rhododendrons are perfect for growing at the edge of a woodland border or shady spot. Plant them in humus-rich acidic soil in a sheltered spot in partial shade or full sun. Mulch rhododendrons annually and water well with rainwater.

Traditional rhododendrons thrive in filtered sunlight and acidic soil. Newer varieties can tolerate a range of sunlight conditions, but always check the plant tag or description when shopping to make sure the plant needs match your garden conditions.

Rhododendrons have no final size and can grow almost indefinitely. They range from dwarf, ground-hugging varieties which may reach 16 in. in 10 years (40 cm) to giant tree-like specimens as tall as 20 ft. or more (6 m). Both moisture and the length of the growing season will have a serious impact on their growth rate.

In fertile soils rhododendrons and azaleas can be grown without receiving further fertilization. In less fertile soils, a complete fertilizer designed for acid-loving plants may be applied in late winter or early spring.

These flowering shrubs light up landscapes with spring blossoms, and their lustrous, evergreen leaves add beauty year-round. Growing rhododendrons isn't difficult as long as you meet their special needs.

Rhododendrons grow in all sizes and shapes - from low growing ground covers, to medium-sized shrubs, to tree-size plants. Some varieties naturally have a rounded, ball-shaped plant habit, others are open and spreading, while other rhododendrons have an upright growth habit.

Coffee grounds are best for fertilizing plants that love acidic, humus-rich soil. These include, for example, hydrangeas, rhododendrons and blueberries.

Rhododendrons need an open soil mixture. Very heavy (clay) and very fine particles (silt) are not suitable. To improve soil, making it more open (i.e containing air pockets) organic matter should be added: leafmould is the best. Alternatives are compost (own or bought), composted bark or conifer needles.

"Many are cultivars of Rhododendron catawbiense, such as the old 'ironclad' varieties like 'Boursault,' 'Nova Zembia,' and 'Roseum Elegans. '" Best of all, they are typically easy to raise—so long as they are in the right spot—and have a long lifespan.

Do rhododendrons need a lot of water? ›

In general, rhododendrons need supplemental water during our dry months. Once every three to four weeks generally works well. The root zone should be moist to at least 8 inches deep. Use a trowel to determine if that is so.

The ideal soil pH for rhododendron plants is somewhere between 4.5 and 6.0. If you have had problems growing rhododendrons in the past, perform a soil test. You can amend the soils with peat moss, compost, and other soil acidifiers to keep them happy. Rhododendrons also appreciate soil that has lots of organic matter.

More rhododendrons are killed by waterlogging and poor drainage than any other cause. If the soil is boggy, heavy clay or compacted, rhododendrons will not grow for long and will likely die. Dark brown dead roots= Phytophthora caused by poor drainage.

The Importance Of Fall Watering

One of the best ways to help combat these two issues is making sure your rhododendron receives plenty of hydration in the fall. Water bushes regularly in the fall until the ground freezes over, especially if rains are inconsistent.

Rhododendrons will grow nicely in full sun to moderate shade. A few Rhododendron varieties such as Caroline', 'Scintillation', Yakushimanum hybrids, 'Hong Kong and the hardy varieties from Finland must have some shade in midday or the foliage will yellow or even burn – especially during a hot summer.

Coffee grounds are best for fertilizing plants that love acidic, humus-rich soil. These include, for example, hydrangeas, rhododendrons and blueberries.