Cape plumbago - Inland Valley Garden Planner

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Cape plumbago — Plumbago auriculata 'Alba'

Description

The cape plumbago is a large vining evergreen shrub with a mounding habit and easily growing 6-8 ft. tall, spreading 8-12 ft. wide. Foliage is comprised of thin medium green leaves, 2 in. long. Showy light blue flowers grow in large 3-4 in. dia. clusters for many months from early spring through fall.

Cape plumbago comes from mild climate zones of South Africa where it grows in bush and scrub thickets on dry slopes. In the Inland Empire, it is well suited to low frost microclimate zones in sunny areas on well-drained soils. Foliage is can be by temperatures below 25°F, but it will quickly regrow in spring. It easily accepts regular moisture and can become quite large and aggressive. Cape plumbago is most commonly planted as a flowering accent shrub and clipped hedge in residential and commercial landscapes. It is also used as a sprawling ground cover on large slopes in parks and open spaces where it can grow in sun and partial shade. Several cultivars have been introduced over the years, including P. a. 'Alba' that has white flowers.

Water Needs

The cape plumbago is well adapted to many soils, full sun and moderate 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. Mature plants can adapt to dry summer conditions when planted on large slopes; some leaves with drop under high moisture stress but will quickly regrow with moisture.

Irrigation Schedule and Graph

Moderate Water Use Plants

Irrigation Schedule 4

	Jan*	Feb*	Mar*	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov*	Dec*
Runs per Month	0x to 3x	0x to 3x	0x to 3x	2x to 3x	2x to 3x	3x to 4x	3x to 4x	3x to 4x	2x to 3x	2x to 3x	0x to 3x	0x to 3x
Inches per Run	1"	1"	1"	1"	1"	1"	1"	1"	1"	1"	1"	1"

Inches per Month	0" to 3"	0" to 3"	0" to 3"	2" to 3"	2" to 3"	3" to 4"	3" to 4"	3" to 4"	2" to 3"	2" to 3"	0" to 3"	0" to 3"

Range of supplemental summer water: 17"-24"
Range of supplemental winter water: 0"-15"

0"-3"

2"-3"

3"-4"

2"-3"

0"-3"

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
Foliage Character: Evergreen
Habit: Upright, Sprawling, Robust, Mounding, Dense, Climbing, Arching, Aggressive
Growth Rate: Fast
Height: 6 ft. - 8 ft.
Width: 8 ft. - 12 ft.
Water Needs: Moderate 4
Foliage Color: Medium green
Flower Color: Blue
Flower Season: Summer, Spring, Fall
Soil Adaptations: Well-draining soil
Exposure Adaptations: Morning sun, Heat, All day sun
Function: Slopes, Screening, Residential spaces, Parks and open space, Grouped, Flowering accent plant, Commercial spaces, Banks, Background plant, Attracts butterflies, Hedge

Maintenance

Prune hard to control growth, or to make it more compact (5). While main pruning is recommended for late winter, before spring growth, in many gardens pruning will be required through out the year to keep mature plants "in bounds." Plants want to get quite large over time, so should usually not be used in small or medium sized gardens (S).

References