Fortunately, there are rhododendrons that can fulfill almost every niche. Some rhododendron species like R. arboreum can eventually become tall trees with large trunks. Others can be dwarf and may grow only a few inches high. The evergreen azalea R. nakaharae can be used as a groundcover. Some species like R. sinogrande have huge leaves on the order of a yard (1 m) in length. Others like 'Kazan' have very small leaves about a half-inch (1 cm) in length. The smallest leaves in the genus belong to R. tsusiophyllum, an evergreen azalea species from Honshu, Japan. Leaf shapes can be oblong, round, pointed, or extremely narrow.

Foliage colors can vary from dark to light green and the leaf surface can be shiny, dull, deeply textured, or hairy. Some forms can have leaves that are blueish, and others can have reddish, orange, or yellow tones. The new growth on many rhododendrons can be very striking, too. Some have stems and leaves that are covered with thick felt-like hairs called indumentum which can make the growth white, tan, or deep rust color. That indumentum will typically remain on the underside of the leaves which can provide an interesting contrasting color dynamic to the plant.

One of the problems with such diversity is that rhododendrons in the wild are adapted to very different conditions depending upon where they grow. Few of us live in locations with a climate that can support them all. Some species are native to alpine regions and require cool weather. They typically suffer in hot, humid climates. Others are adapted to hot, humid conditions and they often cannot take the cold. Others grow in temperate rain forests and require constant moisture. Some may require shade to survive but others may need full sun. Vireya rhododendrons are tropical plants and they cannot withstand frost.

Because so many of us want to grow those diverse forms, we often discover that they will not survive in our more challenging climates. That has resulted in a very active hybridizing program in the American Rhododendron Society. For many years, amateur hybridizers have been crossing plants that are hardy in their regions with the types of plants they want to grow. Hopefully, some of the seedlings they raise will be hardier forms with some of the desired characteristics that will move them closer to the desired goal.

Check out the ARS Seed Exchange and look for some crosses that may have potential in your area. Every time we make a cross, it is similar to shuffling a deck of cards. The more hands we deal, the higher the chance we might get that winning combination. The photo at the top of the page shows a portion of Joe Bruso's garden in Massachusetts outside of Boston. He has raised most of his plants from seed and continues to make extensive crosses breeding for exciting leaf forms.

Note: Special Thanks to Linda Derkach, Joe Bruso, Norm Beaudry, and Mike Stewart who provided some images used in this piece. Their names are indicated below the pictures they took as displayed in this site. All other photos were taken by the author.

Cultivars Pictured to the Left

One advantage with plants that have indumentum, at least in my garden, is that deer in my area do not find that fuzz palatable. Hungry deer will eat almost anything and when pressed they will eventually eat rhododendrons with indumentum. However, at least they are not their first choice for fodder.

Indumentum and tomentum can provide a second striking display after the flowers are gone. As the new growth emerges, it can be covered by those hairs which will make the new leaves a different color. The hues can range from white through shades of cream, tan, brown, or even reddish orange. The colors frequently change as the season progresses and white indumentum will often change to tan or rust color in subsequent months.

Most rhododendrons with indumentum are "elepidotes", a broad grouping for plants that do not have "scales" on their leaf surfaces. Elepidotes include most of the large leaf rhododendrons people associate with the genus like 'Roseum Elegans' or R. maximum. Scales are tiny, waxy glandular structures that can be seen on close inspection. They reside on foliage and plant parts, and especially on the undersides of the leaves. Those plants belong to the second grouping, "lepidotes". Lepidotes include familiar plants like 'P.J.M.' or R. augustinii.