Sunday, August 14, 2011

Plumbago

Ceratostigma
Among my favorite groundcovers, though needing some space, the Plumbago is guaranteed to give a long season of bloom followed by excellent fall color. They are also very easy to grow, rarely being bothered by pests or disease. During cold winters, Plumbago may died back to ground level. Do not worry, they will resprout vigorously during late spring and will bloom later the same summer. Plumbagos bloom on current seasons growth. Propagation is from softwood cuttings taken during mid summers. Clumps can also be divided during early spring.

Ceratostigma griffithii ( Griffith's Plumbago )
A low, dense mounding, evergreen shrub, that is native to warm valleys of Bhutan.
Some records include: 1 year - 3 x 3 feet; largest on record - 4.5 x 8 feet
The leaves, up to 3 x 1.5 inches, are mid green, turning to red in autumn.
The bright blue flowers are borne in terminal clusters during late summer and autumn.
Hardy zones 7 to 10 on well drained soil. Drought tolerant, even tolerating dry shade under pines.

Ceratostigma plumbaginoides ( Groundcover Plumbago )
Also called Leadwort. Rapid growing, long lived, bushy and clump forming, perennia, reaching up to 20 inches x 7 ( rarely over 1 foot in height ) feet if not contained. It can spread up to 3 feet in 3 years and while well behaved on some sites; its rhizomes can become invasive on lighter moist soils. It has wiry stems and a woody base. Groundcover Plumbago is native to China and is highly valuable as a border plant, large scale groundcover and also looks great trailing over stone walls. Groundcover Plumbago looks great in front of Pennisetum grasses.
The foliage is deciduous to semi-evergreen in mild climates. The oval leaves, up to 4 x 2 ( usually half that ) inches in size, are glossy mid-green. They turn rich maroon red during late fall. Plumbago is late to appear during spring and can be mixed with spring bulbs, esp Crocus's.
The tubular, brilliant light blue flowers, up to 0.8 inches in length are borne from July to October. Plumbago looks awesome planted with Moonbeam Coreopsis.
It can be propagated from suckers or by dividing clumps during early spring. Hardy from zones 6 to 9 ( zone 5 against a warm south facing wall if protected in winter, preferrably with Pine Mulch ) in full sun to partial shade on moist, well drained soil. It should be cut to ground in March before new growth begins. Disease free, deer resistant and very heat tolerant but does not like winter wetness.

* photos taken on summer 2006 in Howard County, MD


* photos taken on 4th of July 2010 @ U.S. National Arboretum, D.C.



* photos taken on July 17 2010 @ Morris Arboretum, Philly, PA


* photos taken on Aug 20 2011 @ Brookside Gardens, Wheaton, MD


* photos taken on Sep 17 2015 in Columbia, MD


Ceratostigma willmottianum ( Chinese Plumbago )
A fast growing, open low deciduous shrub, that is native to Tibet and western China. Some records include: largest on record - 6.5 x 6 ( usually much lower ) feet. It can be a rhizomatous spreader. In very cold climates it may act more like a perennial, in mild climates it can be cut to near ground level during early spring and treated as a perennial for more attractive denser habit.
The bristly, pointed oval to elliptical leaves, up to 2 x 1 inches, are medium green turning to red in autumn.
The rich mid blue, tubular flowers are borne all summer and long into fall.
Hardy zones 6 to 10 in full sun to partial shade on just about any moist, fertile, well drained soil. Tolerates drought but prefers moister conditions.
In colder parts of its range, it may die back to the ground during the winter, cut back hard during early spring and it will regrow rapidly.
Propagate from softwood cuttings taken during summer.

* photos taken by Milan Havlis ( havlis.cz )


'Desert Skies'
Attractive yellow foliage contrasts well with the blue flowers.

* photo taken on 4th of July 2010 @ U.S. National Arboretum, D.C.




'Forest Blue'
Deep blue flowers.

'My Love'

* photo taken on Sep 23 2013 in Burtonsville, MD

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