But that doesn't have to be the case. Here's a list of compact Rhododendrons that won't outgrow their welcome.
'Bow Bells' -- 3' -- deep pink buds, light pink flowers
'Cilpinense' -- 3' -- blush pink flower touched with deeper pink; blooms early
'Daphnoides' -- 4' -- unusual foliage, glossy green rolled leaves; purple flowers
'Dora Amateis' -- 3' -- white flower; fragrant
'Impeditum' -- 2' -- purple flower; gray green foliage
'Kimbeth' -- 3' -- deep pink buds through winter open to rosy, red-pink blooms
'Mardi Gras' -- 30" -- pink, blushed white flowers
'Molly Ann' -- 2' -- rose-pink flowers
'Mrs. Furnival' -- 4' -- light pink with striking blotch in center of flower
'Novo Brave' -- 3' --bright pink with a red blotch in center
'Patty Bee' -- 18" -- clear yellow flowers
'PJM' -- 4' -- tolerates cold, heat and sun; blooms early; bright lavender pink flower
'Ramapo' -- 2' -- pinkish-violet flower
'Rosamundi' -- 4' -- light pink flower, blooms very early in the year
'Sapphire' -- 30" -- light blue flowers; fragrant
'Scarlet Wonder' -- 2' -- glossy green leaves; brilliant red bloom, award winner
'Snow Lady' -- 30" -- white flowers resemble fallen snow; early bloomer
'Unique' -- 4' -- bright pink buds open to buttery yellow bloom
R. yakushimanum (also called "yaks") -- several cultivars, including 'Yaku Angel,' 'Mist Maiden,' and 'Ken Janeck' -- 1' - 4' depending on the cultivar; very hardy; pink buds open to pink-turning-white, bell-shaped flowers; resistant to root weevil
For more information on rhododendrons, I recommend Greer's Guidebook to Available Rhododendrons, by Harold Greer. I've used my copy so much, it is literally falling apart. It's held together now with scotch tape. This book is considered by many to be "the bible" on rhododendrons with descriptions and ratings of hundreds of cultivars. He includes color photos of many flowers, as well.
