All About Gibraltar Azaleas

Gibraltar azalea plant with orange flowers.
David Beaulieu

Gibraltar azalea is a deciduous flowering shrub. Plant taxonomy classifies these orange azaleas as Rhododendron 'Gibraltar.' Occasionally, you will see the name written as Rhododendron x 'Gibraltar' (the insertion of the "x" in the name calls attention to the fact that this is a hybrid plant). The shrub is part of the Exbury group of hybrids. The parents of Exbury hybrids are of diverse geographical origins.

Characteristics

Gibraltar azalea plants produce clusters (called "trusses," technically) of funnel-shaped, bright orange flowers with ruffled petals in May (in a zone 5 garden). Flowers precede leaves. Plants can achieve a height of five to six feet after 10 years if not pruned to minimize their vertical growth; with their upright growth habit, the width tends to be less than the height.

Planting Instructions

These bushes are suitable for planting zones 5-8. Grow in filtered sunlight or partial sun and well-drained soil with an acidic soil pH. If your soil type is a clayey soil, work in soil amendments such as compost to improve drainage before trying to grow this plant.

Uses in Landscaping

Because these orange azaleas bear colorful flowers in spring, some like to use the bushes as foundation plants. As deciduous shrubs, however, they will provide neither a buffer to cold winds nor a point of visual interest in winter. Therefore, they should not be your first choice in a foundation planting. Some prefer them as specimen plants. When used in a woodland garden, plant them in a relatively sunny spot.

These are poisonous plants. Make sure they are out of reach of children and pets, who may accidentally ingest them.

Mulching, Pruning, Fertilizing

These shallow-rooted plants like their "feet" kept cool, and you can accomplish this by applying mulch around them. Since they bloom on old wood, prune them just after blooming if you prune them at all (Exbury azaleas generally are not pruned much). Make clean cuts (back to a major branch). You have to be careful about the time of year in which you fertilize: Fertilizing should be done in spring. Otherwise, you will be promoting tender new growth too late in the year—growth that will be damaged in cold weather. Specialty fertilizers are sold for these plants that will contain ammonium-N (which will also lower soil pH).

Attracting Wildlife

As attractive as such colorful bushes are to humans, they are just as attractive to some of the wildlife we most enjoy watching in our landscapes. These orange azaleas are plants that attract butterflies and are also useful in hummingbird gardens.

Deciduous vs. Evergreen

While some shrubs in the genus, Rhododendron are evergreen, Gibraltar azaleas are deciduous. This fact holds two ramifications of significance to the gardener:

  1. Deciduous types are more sun-tolerant than evergreen types (although, in the South, you will still want to be careful not to give them excessive sunlight). At least dappled sunlight is required for optimal blooming on Gibraltar azaleas.
  2. Deciduous types offer virtually no interest in the winter landscape.

More Care Tips

Examples of other orange azaleas hardy to at least zone 5 include:

  • 'Golden Lights': a golden-orange azalea
  • 'Mandarin Lights': a bright orange azalea
  • 'Golden Oriole': its flowers are orange in the bud stage.

Proper Gibraltar azalea care begins at planting time. Because they are shallow-rooted bushes, dig a wide planting hole when installing these orange azaleas. Preparing a hole of generous width will give the roots friable soil into which they may expand.

Water well during the first couple of years or so, to help the plants become established. There is a tricky balance to keep between sufficient watering and over-watering, but the latter is much easier to avoid if you ensure that the soil is well-drained.