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The Island snapdragon is an evergreen shrub with arching stems that develops a dense and sprawling habit, growing to 3-4 ft. high and 8-10 ft. wide. Leaves and stems are smooth and distinctively lime green; small clusters of red tubular owers that grow on the tips of stems are bright and colorful from spring through mid-summer.

The Island snapdragon is native to several offshore islands of California where it grows in scrub vegetation with moist winters and dry summers. It has proven to be a very popular plant for hummingbirds, and is well adapted to Inland Empire climate conditions in full sun, on many types of soil and with low amounts of summer moisture. It provides fresh green foliage character and intense red flowering along borders, on banks and around bioswales.

Several cultivars of Island snapdragon are available from different sources. One choice, G. s. 'Firecracker' is a smaller and tighter growing selection, 2-3 ft. wide and 4-5 ft. across. It's leaves and stems are covered with fuzzy hairs and it produces larger deep red flowers than the species. G. s. 'Bosa Roca' is another compact selection with deep red flowers, fuzzy stems and dense mounding habit. The flowers on this cultivar tend to flair open like the popular annual snapdragon.

Water Needs

Island snapdragon grows best in sunny garden locations on well drained soils and with low amounts of supplemental water during summer. The chart shown below provides a recommended baseline guide to the monthly irrigation schedule and volume of supplemental water needed to maintain healthy growth throughout the average year. It should be noted there are several months indicated by an asterisk (*) when winter rains can provide sufficient moisture and irrigation is not needed. The high and low range of moisture indicates it can grow with varying amounts of water; more moisture during spring helps achieve a more robust and longer flowering cycle.

Irrigation Schedule and Graph

Low Water Use Plants

Irrigation Schedule 2

  Jan* Feb* Mar* Apr May Jun Jul Aug Sep Oct Nov* Dec*
Runs per Month 0x to 2x 0x to 2x 0x to 2x 1x to 2x 1x to 2x 1x to 2x 1x to 2x 1x to 2x 1x to 2x 1x to 2x 0x to 2x 0x to 2x
Inches per Run 1" 1" 1" 1" 1" 1" 1" 1" 1" 1" 1" 1"
Inches per Month 0" to 2" 0" to 2" 0" to 2" 1" to 2" 1" to 2" 1" to 2" 1" to 2" 1" to 2" 1" to 2" 1" to 2" 0" to 2" 0" to 2"

Range of supplemental summer water: 7"-14"
Range of supplemental winter water: 0"-10"

  Jan* Feb* Mar* Apr May Jun Jul Aug Sep Oct Nov* Dec*
For more information on how to use this Irrigation Schedule and Graph, follow this link.

For information how to calculate your irrigation system’s schedule and precipitation rate, please follow this link.

Plant Properties

Plant Type: Shrub, Native
Foliage Character: Evergreen
Habit: Mounding, Dense, Compact
Growth Rate: Fast
Height: 3 ft. - 4 ft.
Width: 8 ft. - 10 ft.
Water Needs: Low 2
Foliage Color: Pale green
Flower Color: Red
Flower Season: Summer, Spring
Soil Adaptations: Well-draining soil
Exposure Adaptations: Morning sun, All day sun, Partial sun
Function: Hummingbird plant, Foundations, Flowering accent plant, Container plant, Banks, Background plant


If grown in shade, and looking "leggier" than desired, pinch back stems to encourage bushier growth (5). If damaged by frost in the winter, wait a few weeks before pruning damaged areas. You will want to be sure of the extent of the damage first, and the damaged parts can help protect healthy tissue if the cold spell lasts over a few nights (1). If the plant looks to be in need of "refreshing," it can be cut all the way to the ground in late winter, before spring growth, and it will grow back, rejuvenated (7).



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