What a difference a year makes. This spring in 2015, at the Gardens, April showers have brought lots of April flowers, including some large evergreen rhododendrons that didn’t bloom last year until May.
Just to clarify, all azaleas are rhododendrons, but not all rhododendrons are azaleas. The genus Rhododendron includes many different types of hybrids, natives and cultivars. Some are evergreen and others are deciduous. There are large leaf selections and some with small foliage too. At Gibbs Gardens, we grow over 100 different cultivars of evergreen rhododendrons. Most varieties will thrive in acid soil and in a location that receives at least part shade from the hot afternoon sun. Good companions include the shrub mountain laurel, Kalmia latifolia, and ferns, both native and exotic types.
I am a big fan of native azaleas, which, for the most part, are easy to grow. Mostly deciduous, they are well behaved both in the garden and in the wild. Once they finish blooming, their spent blossoms seem to disappear, unlike some of the hybrid azaleas whose faded flowers hang around even when you wish they wouldn’t. Earlier in April, the piedmont azalea, Rhododendron canescens was delightful, filling the air with its sweet scent. Some in the Gardens are easily 10’ tall and thought to be over 100 years old. On one hillside adjacent to the stream in the Japanese Garden, Jim thinned out the canopy to allow more light for the native azaleas. With more light, there were more flowers and the plants are flourishing.
In late April, near the Manor House, I was excited to see the flame azalea, Rhododendron calendulaceum. Although they are not fragrant, the striking flowers, which range from yellow to orange to scarlet, put on a show for several weeks.
Late in May or early June, the swamp azalea, Rhododendron viscosum, will fill the air with its perfume. This native flowers after the leaves appear. Depending on the location, it can reach 5 to 12’ tall. While it tolerates wet soils, the swamp azalea will also grow in average garden soils, provided it gets regular water.
With some thought and planning, you can have a variety of rhododendrons and azaleas blooming from early spring through summer.