[above R. Catawba 'Lee's Dark Purple' available at Merrified and elsewhere, blooms again in fall]
Rhododendron spp.| Rhodies & Azaleas
I don’t actually think it’s possible to have a Top 10, I just said that to get your attention. But here is my list of those I like. I’ll try to keep it reasonable, not too short, not too long but as reliable as possible. In fact there are over 900 species and countless cultivars, improvements have come with hybridization, especially for cold hardiness, so don’t fear change in this case. Rhododendrons and azaleas are indigenous to many parts of the world but grow especially well in the US Piedmont and upper Northwest, as well as In China and Japan.

NOTHING. They are all now classified in the same genus so there is no clear distinction for purposes of ID, but there are a few generalisms you can work with (eventhough it doesn’t really matter). Rhododendrons are mostly evergreen, while azaleas are mostly deciduous. Rhododendrons mostly have 9 stamens, while azaleas mostly have 5 – this info is straight from Dirr. It seems to me that rhododendrons have large leaves, while azaleas have small. The truth is that they are now so hybridized that it virtually impossible for experts to tell the difference. So the best thing to do is not distinguish between rhododendrons and azaleas, but between size, color and texture. I will include the name I found each with in the nursery.

Puny 18 inch midgets to 15 foot giants, all shrubs, many everygreen, especially in the Mid-atlantic. Some people adore them, some abhore because of overuse and loud colors. I’m in the first camp, though, especially for the larger leaved woodlanders. The big flower buds have a creamy frosting texture to me. I love Asian Modern gardens where they are right at home showing off their strong branch architecture. They make great foils for ferns and stone. They are more perky than Viburnums but also more finicky. Still, on the whole very versitile for residential landscapes. Don’t hate them just because they are beautiful.

Watch out for aphids, though the worst problem seems to be that people plant them from nursery containers which has great soil, straight into a container sized hole in the clay ground. Make the effort when planting to dig a hole 2 to 3 times the width and 1.5 time the depth of the container, then mix clay from the site with a good mix of leaf grow 50/50 and plant very shallow to allow for good drainage and air circulation. Doing this will keep the suffering and death tole down. Then be sure to soak the soil thoroughly once a week till established. Does well with an elevated bed of top soil, since it has very shallow roots. Once established, it doesn’t like to be disturbed. Mulch seasonally 2″ to 3″.

In production, growers are pushing plants to their limits so they will look great at the retail nursery, feeding and watering them to get them ready. It reminds me of professinal athlete and steroid use. So watering is very important when you first plant. Don’t place white ones at front door unless you want to pick off the spent blooms.
SOIL acid lover, REQUIRES good drainage
Native Blueridge Mountains, Carolina, Tennessee
ZONES HARDINESS | SUN OR SHADE ….. 4,5 – 8 | part sun to full shade
GROWTH RATE ….. slow, once established can be very long lived, 40 years or more
PLANT SHAPE & BRANCHING ….. (unless noted) Rounded outline, multistemmed, woody reaching branches
LEAF ARRANGEMENT ….. simple, alternate, all the leaves are thick but I will reserve teh term “leathery” here for the thickest, heaviest
LEAF SIZE ….. for simplicity, I’m going to put the leaves into catagories: tiny=.5″ or less, small=.5 “to 1.5″, medium=1.5″ to 3″, large= 3″ to 6″

Great list and pictures of specimens some UNC dude grew in his own garden, must be big
Merrifield Nursery in Northern VA Rhododendron and Azalea chart
Wagner Nursery in Oregon has nice photos
dogwood*design Flickr Rhododendron set

Rhododendron catawbiense | Catawba Rhodie ['Album' above] widely available, long time standard, sometimes referred to as Mnt. Laurel, but that’s NOT what it is.
HEIGHT / WIDTH ….. 6′-10′/5′-8′
LEAF SIZE, FORM & SHAPE ….. small, eliptical
LEAF COLOR ….. Evergreen | medium to dark green, uniform
FLOWERS | 2″ lilac, purple, rose or white mid May, single

‘Del Val White’ azalea [above] available at Merrifield, pretty and frilly
HEIGHT / WIDTH ….. 4′/4′
LEAF SIZE, FORM & SHAPE ….. large, eliptical, narrow, leathery, heavy
LEAF COLOR ….. Evergreen | dark green, handsome
FLOWERS | pure white, single frilly, girly, March to April

Encore hybrid series ‘Autumn Amethyst’ or ‘Autumn Royalty’ [above] known for spring AND fall bloom, newish, Ray’s favorite
HEIGHT / WIDTH ….. 4′/4′
LEAF SIZE, FORM & SHAPE ….. medium, elongated eliptical or spear, soft and fuzzy, leathery but not thick, dark cast in winter
LEAF COLOR ….. Evergreen | medium, spear, similar to Satsuki hybrids
FLOWERS ….. Amethyst to dark pink, large single bloom

‘Klondyke’ Exbury hybrid [above], available at Merrifield, Bold display, good in woodland or modern styles
HEIGHT / WIDTH ….. 6′-8′/4′-6′
LEAF SIZE, FORM & SHAPE ….. medium, spear
LEAF COLOR ….. Evergreen | lighter green with orangey new growth
FLOWERS | single, tangerine orange, ruffled

‘Macranthra Double’ Indica Type [above], available at Merrifield, compact and dense, good for little spaces, spreading
HEIGHT / WIDTH ….. 18″-24″/3′
LEAF SIZE, FORM & SHAPE ….. small, spear
LEAF COLOR ….. Evergreen | lighter green, not as thick
FLOWERS | double, large, rose-like bloom, coral-pink, pretty

R. x ‘Nova Zembla’ available at Merrifield, hardy to -25 and can take more sun than other Rhodies. Cool speckled throat on red, red flowers.
HEIGHT / WIDTH ….. 4′-5′/4′-7′
LEAF SIZE, FORM & SHAPE ….. large, eliptical
LEAF COLOR ….. Evergreen | dark green
FLOWERS | profuse, single, ruffled, red (NOT hot pink)

PJM hybrid series ‘Elite’ [above] available at Bluemont Nursery, vigorous, none for it’s terrific hardiness. They are a bit tougher than most. Not my favorite, but could be the only choice for some conditions.
HEIGHT / WIDTH ….. 4′-6′/4′-7′
LEAF SIZE, FORM & SHAPE ….. medium, eliptical
LEAF COLOR ….. Evergreen | dark green, turning plum in fall, thick
FLOWERS | lavendar purple in April, single

‘Rosebud’ azalea [above] available at Merrifield, well named! Dave’s Garden has nice pics.
HEIGHT / WIDTH ….. 2′-3′
LEAF SIZE, FORM & SHAPE ….. small, eliptical
LEAF COLOR ….. Evergreen | lighter green
FLOWERS | clear pink in April to May, double

‘Silver Sword’ azalea [above], maybe R x kaempferi, has lovely and rare variegated folliage, may not be so hardy, only to the bottom of zone 6, but I’m going to give it a try, cool! Available at Merrifield.
HEIGHT / WIDTH ….. 4′/3′
LEAF SIZE, FORM & SHAPE ….. small, spear
LEAF COLOR ….. Semi-evergreen | bright green on inside, rimmed with white, pretty
FLOWERS | single, rose to red, largish