Rhododendrons for spring colour
Rhododendrons are beautiful, evergreen flowering plants. They are often given a bad name because of one species, Rhododendron ponticum, that is taking over large areas of countryside. However, hybrid garden varieties are not invasive and can provide fantastic displays of colour in spring. They need an acid soil (a soil with a pH of about 5.5). Most acid soils are either peaty or sandy. Clay soils are often not acid enough. You can easily test your soil with a pH testing kit and if you don’t have an acid soil, you can grow many dwarf varieties in pots and containers.
Alternatively, as long as you don’t have chalk in the soil, you can dig a hole and fill it with ericaceous compost. In future years, you can mulch once a year with Irish moss peat (as this has a pH of about 4) and/or feed with sulphur, aluminium sulphate (Hydrangea colourant) or ferrous (iron) sulphate. The variety that will tolerate the highest pH (least acid soil) is probably Rhododendron Cunningham’s White.
There are many different types of Rhododendrons species and some have these have been crossed by plant breeders to produce the beautiful, large flowered Hybrid Rhododendrons such as Furnival’s Daughter (picture aboved).
There are also dwarf rhododendrons, including the Yakushimanum (or Yak for short!) varieties that do not grow taller than 60-100cm (approx 2-3ft) tall. Some of these are named after the seven dwarfs with the best being Sneezy, Sleepy, Dopey, Grumpy and Bashful.
Azaleas are also Rhododendrons and there are the evergreen hybrid azaleas mainly bred in Japan and the deciduous hybrid azaleas. Many of the evergreen hybrid azaleas are also good in pots as most do not grow more than 1.2m (4ft) tall. The beautiful Vuyk’s Scarlet is a wonderful example of these.
Deciduous azaleas include the wonderfully scented Azalea pontica (Rhododendron luteum) with its beautiful yellow flowers in March and April. One of the best.