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Rhododendron, Azalea 'Gibraltar'


Family: Ericaceae (er-ek-AY-see-ee) (Info)
Genus: Rhododendron (roh-do-DEN-dron) (Info)
Cultivar: Gibraltar
Additional cultivar information:(Knap Hill hybrid)
Hybridized by de Rothschild
» View all varieties of Azaleas and Rhododendrons
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4-6 ft. (1.2-1.8 m)


4-6 ft. (1.2-1.8 m)


USDA Zone 5b: to -26.1 C (-15 F)

USDA Zone 6a: to -23.3 C (-10 F)

USDA Zone 6b: to -20.5 C (-5 F)

USDA Zone 7a: to -17.7 C (0 F)

USDA Zone 7b: to -14.9 C (5 F)

USDA Zone 8a: to -12.2 C (10 F)

USDA Zone 8b: to -9.4 C (15 F)

USDA Zone 9a: to -6.6 C (20 F)

USDA Zone 9b: to -3.8 C (25 F)

Sun Exposure:

Sun to Partial Shade


All parts of plant are poisonous if ingested

Bloom Color:



Bloom Time:

Late Spring/Early Summer



Other details:

Unknown - Tell us

Patent Information:


Seed Collecting:

N/A: plant does not set seed, flowers are sterile, or plants will not come true from seed

Foliage Color:

Unknown - Tell us

Bloom Characteristics:

Unknown - Tell us

Water Requirements:

Average Water Needs; Water regularly; do not overwater

Where to Grow:

Unknown - Tell us


This plant has been said to grow in the following regions:

Huntsville, Alabama

Hattieville, Arkansas

Garberville, California

Chicago, Illinois

Canada, Kentucky

Lancaster, Kentucky

Pikeville, Kentucky

Alfred, Maine

Edgewater, Maryland

Valley Lee, Maryland

Mashpee, Massachusetts

Charlotte, North Carolina

Gibsonburg, Ohio

Lakewood, Ohio

Lansdale, Pennsylvania

Conway, South Carolina

Virginia Beach, Virginia

Madison, Wisconsin

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Gardeners' Notes:


On Mar 25, 2012, wildbarrett from Lakewood, OH wrote:

LOYAL & GORGEOUS! Mine is 23 yrs planted, sits in floods every spring, has been through grape attacks, groundcover attacks, you name it! Now my ancient beech down from a storm last yr, my Gib had too hot sun last summer. So in fall, planted a JapWhitePine to southwest to build lateday summer sun protection. She's a lady and hates to share her ground. Give her sweet peat, bagged compost, holly food, lateday shade, plenty of moisture, and keep her mulched feet clear of other plants for easy fert access, and branches fully clear of neighboring plantings. Every yr rewards me with the most stunning GLOWING TANGERINE TRESSES!! Oh, once done blooming, CAREFULLY remove bud ends of spent flowers, as the new growth emerges just at the same juncture. Use fingers, and pinch gently away, watching... read more


On Jun 6, 2010, gardencart from North Aurora, IL wrote:

I have four of these and all but one are really struggling. I haven't tested the soil yet, but suspect that winter protection might be critical, because the one that does bloom is somewhat 'nestled'. Just an observation. They are in full sun, which should be ok. Anybody have any suggestions? What time of year would it be ok to possibly move them?


On May 22, 2010, kittenzzz from Canada, KY wrote:

This plant grows beautifully here and is an extremely reliable bloomer! Maybe because some of its ancestors are native to this part of the south-central Appalachian Mountains. It grows quickly once established. It grows much better when it has deep, moist, well-drained soil, morning sun, and filtered afternoon shade, and it likes its roots to be shaded by a mulch or, better yet, groundcover or moss. It's pretty forgiving as long as it doesn't stand in water or scorch to death all day in unrelenting sun.

I used to have several plants. They were destroyed in a construction project & I've been looking for it for several years; it's an older variety and not so easy to find in the trade anymore. It's fairly easy to start from cuttings.


On May 28, 2008, Sabrina1978 from Gibsonburg, OH wrote:

I've been 'growing' this for three years. I have not had it bloom yet, nor has it gotten any larger.....

Having said that -I have HEAVY clay, neutral to slightly alkaline soil, so I knew it was going to be a challenge. I moved it this year adding lots of peat, planting above soil line, and in a part shade spot. It seems to be doing much better. How long that will last time will tell.

I'll report if I ever get it to bloom.

UPDATE on 5-19-09 It actually looks as if it might bloom, albeit only a bit. It looks pretty scraggly so once it blooms I'm going to trim it to a nicer shape and hope that it thrives in this new location.


On Jan 26, 2006, raisedbedbob from Walkerton, VA (Zone 7a) wrote:

Beautiful when it blooms which doesn't happen regularly in my experience. Very slow grower.