Tuesday, June 14, 2011

Blue Spirea

Caryopteris
A genus of 6 species of long lived, woody perennials and shrubs ( depending upon climate ) that are part of the larger Verbena family. All species are native to Asia from the Himalayas eastward. They are great for massing and shrub/perennial borders.
The typically silvery foliage on most species is somewhat aromatic and is oppositely arranged.
The fragrant flowers are borne in terminal and axilliary clusters from late summer into autumn. The flowers attract hummingbirds and butterflies.
Hardy zones 6 to 9 in full sun ( tolerates partial shade but not as dense ) on dry to average, loamy, well drained soils.
They are deer/rabbit resistant, drought/alkaline tolerant and rarely bothered by insect pests or disease. They look best pruned back hard to about 6 inches in height during very early spring to encourage vigorous growth and abundant flowers ( they bloom on current years growth ). Plants not cut back during early spring often become overly dense, loose vigor and flop over. It is recommended to plant Blue Spirea during spring since plants do need to be fully established to survive a severe winter.
Propagation is from hardwood cuttings taken during winter or soft tip or semi-ripe cuttings taken from late spring to early fall. Cuttings are generally easy to root.

Caryopteris x clandonensis ( Blue Mist Spirea )
An erect, vase-shaped, bushy, woody perennial or deciduous shrub ( depending upon climate ) reaching a maximum size of 6 x 6.5 feet, that is a hybrid between Caryopteris incana & C. mongolica. Can be used as a low informal hedge. Looks great mixes with bright pink Chrysanthemums.
The aromatic, toothed, lance-shaped or narrow oval leaves, up to 4 inches in length, are downy gray-green.
The violet-blue or deep blue flowers are borne in dense cymes from late summer to mid autumn. The Blue Mist Spirea flowers on current years growth.
The flowers attract butterflies.
Hardy zones 4 to 9 ( acting more like a perennial in zone 4 and 5 ) in full sun to partial shade on dry, light, fertile, well drained soil that is mulched ( especially during winter ). Very drought tolerant. Cut back hard to about 4 inches in height, during early spring to promote fresh growth and better flowering. It has been known to survive as low as -40 F as a perennial if planted on a sheltered site with heavy mulch. In cooler summer climates such as England, they thrive best in a warm site protected from excessive wind.

* photos taken on Aug 28 2011 in Columbia, MD


* photo taken on Sep 15 2011 in Howard Co, MD

* photos taken on May 26 2012 in Ellicott City, MD

* photo taken on July 30 2013 in Grand Bend, Ontario

* photos taken on Sep 3 2013 in Ellicott City, MD

* historical archive photo


'Arthur Simmonds'
An improved form reaching a maximum size of 5 x 7 feet, but otherwise similar.

* photos taken on Aug 30 2012 in Columbia, MD


'Azure'
Bright blue flowers.

'Blue Balloon'
Vigorous but compact in habit, reaching a maximum size of 6 x 6 ( rarely over 3 x 4 ) feet in height, bearing intense blue flowers.
The foliage is mid-green above, silvery beneath.

* photos taken on Oct 5 2015 in Columbia, MD

* photos taken on Aug 5 2016 in Columbia, MD

* photos taken on Nov 14 2016 in Columbia, MD


'Blue Mist'
Vigorous but compact in habit, reaching a maximum size of 4 x 6 feet.
The flowers are blue.

* photos taken on Sep 5 2012 in Columbia, MD


'Dark Knight'
Upright and compact in habit, reaching a maximum size of 6 x 8 ( rarely over 4 ) feet, with abundant, rich deep blue-purple flowers during late summer and early autumn. Some records include: 2 years - 3 feet.
The foliage is silvery-green.

* photos taken on August 1 2013 in Stratford, Ontario

* photos taken on May 27 2017 @ Meadowlark Botanical Gardens, Vienna, VA



'First Choice'
Compact, erect and dense in habit, reaching up to 3 x 3 feet in 5 years with an eventual maximum size of 4 x 5 feet.
It has glossy, deep silvery-green foliage and abundant, deep purplish-blue flowers borne mid-summer into early autumn. Later blooming than most, it can be mixed in plantings with 'Longwood Blue' for a longer season of bloom.
Hardy zones 5 to 8. Pest and disease resistant and remains attractive even if not cut back during early spring.

* photo taken on Aug 29 2013 in Clarksville, MD

* photo taken on Sep 21 2013 in Howard Co., MD

* photos taken on Oct 24 2014 in Ellicott City, MD


Caryopteris 'Good as Gold'
Compact in habit, reaching up to 4 x 4 feet.
The foliage is intense golden-yellow.
The flowers are intense bluish-purple.
Hardy zones 5 to 8.

* photos taken on May 24 2017 in Columbia, MD


'Grand Bleu'
Dense and compact in habit, reaching a maximum size of 4 x 3 ( rarely over 3 ) feet.
The attractive glossy deep green foliage contrasts with very profuse, dark violet-blue flowers borne over a long season during mid to late summer.

* photo taken on Aug 29 2013 in Clarksville, MD

* photos taken by Milan Havlis ( havlis.cz )

* photo taken on July 7 2016 in Elkridge, MD

* photo taken on Oct 2 2016 in Bel Air, MD


'Heavenly Blue'
Dense and somewhat compact, reaching a maximum size of 5 x 6 feet.
The flowers are deep blue.

* photo taken on Oct 6 2012 in Ellicott City, MD

* photo taken by Milan Havlis ( havlis.cz )


'Kew Blue'
Originated as a seedling of 'Arthur Simmonds' with foliage that is deep gray-green above and silvery below. The flowers are deep blue.

'Lil' Miss Sunshine'
Compact in habit, reaching up to 3 x 3 feet.
The glossy foliage is intense yellow in color.
The abundant, deep blue flowers borne during late summer are in stunning contrast to the foliage.

* excellent video found on internet


'Longwood Blue'
Reaches a maximum size of 4 x 5.4 feet, with silvery-gray foliage and profuse, bright blue to violet-blue flowers borne late summer into early autumn.

* photo taken on Sep 29 2013 in Ellicott City, MD

* photo taken on May 27 2017 @ Meadowlark Botanical Gardens, Vienna, VA


'Petit Blue'
Compact and dwarf in habit, reaching up to 2.5 x 4 feet.
The foliage is glossy deep green.
The abundant flowers are deep blue.

'Summer Sorbet'
Reaches up to 3 x 3 feet in just 3 years with an eventual size of 4 x 4 feet.
The attractive bright green foliage is boldly variegated with a broad bright yellow border.
The brilliant, violet-blue flowers are borne during late summer into mid-autumn.

* photo taken by Milan Havlis ( havlis.cz )


'Sunshine Blue'
Reaches up to 5 x 7 ( averaging 3 x 4 ) feet, with bright golden-green foliage contrasting with deep purple-blue flowers borne late summer to mid autumn.

* photos taken on Aug 25 2011 @ Scott Arboretum, Swarthmore College, PA



White Surprise'
Originated as a sport of Caryopteris ‘Heavenly Blue’. Dense and compact in habit, reaching a maximum size of 3 x 4 feet.
The abundant, bright blue flowers contrasts spectacularly with the rich green foliage that is boldly variegated with a white margin.

'Worcester Gold'
Reaches a maximum size of 5 x 5 ( rarely over 4 ) feet, with very attractive foliage that remains bright golden-yellow all summer long, finally fading to bright golden-green before falling during autumn. The very showy, intense bright blue flowers are borne during late summer.
Hardy zones 5 to 9 ( 4 if protected ).

* photos taken by Milan Havlis ( havlis.cz )


Caryopteris divaricata
A rare, vigorous shrubby perennial or shrub, reaching a maximum size of 7 x 4 ( averaging 5 ) feet, that is native to woodland edge in eastern China, Korea and much of Japan. It is more woody in habit than other Caryopteris.
The ovate leaves are up to 5.5 x 2 inches in size. The foliage is mid-green.
The very showy, fragrant, relatively large flowers, up to 0.4 inches long, are deep blue. They are borne late summer to mid-autumn.
Hardy zones 7 to 9 ( 5 & 6 as perennial ).

'Blue Butterflies'
An exceptionally vigorous form, reaching up to 6 x 7 feet; it is otherwise identical to the species.

'Snow Fairy'
Reaches up to 4 x 7 feet, with luxuriant green foliage that is boldly variegated with a white margin.
The bright blue flowers are borne during late summer.
It is among the most beautiful of variegated shrubs.

* photos taken om June 23 2013 @ U.S. National Arboretum, DC

* photos taken on Oct 17 2013 in Olney, MD


Caryopteris 'Gold Giant'
Vigorous in habit, reaching up to 4 x 4 feet, with golden-yellow leaves and mid blue flowers. The black stems contrast well with the foliage.
Hardy zones 6 to 9 ( 5 as perennial ).

Caryopteris incana
An arching small evergreen shrub, reaching a maximum size of 6.5 x 6.5 feet, that is native to China and Japan.
The toothed, pointed leaves, up to 4 inches in length, are grayish.
The silvery-blue flowers are borne in spirea-like clusters during late summer.
The stems are slender.
Hardy zones 7 to 10 as a shrub, it can be grown as a perennial in much colder climates, possibly surviving as low as -50 F or colder if planted on a protected site and deeply mulched during winter.

Caryopteris x indica 'Hint of Gold'
A deciduous shrub, reaching up to 3 x 4 feet.
The golden-yellow later turning golden-green foliage is larger than that of other Caryopteris. The foliage contrasts well with the blue flowers.
Hardy zones 6 to 9

* photo taken on Aug 29 2013 in Clarksville, MD

* photo taken on June 11 2014 in Clarksville, MD



Caryopteris mongolica ( Mongolian Blue Spirea )
An erect small shrub, reaching a maximum size of 5 x 3 feet, that is native to Mongolia and north-central China.
The toothed, narrow leaves, up to 2 inches in length, are gray-green.
The rather large, rich blue flowers are borne on terminal spikes during late summer.
The stems are slender.
Hardy zones 2 to 7 in full sun on well drained soil. It requires a continental climate with very hot summers and very cold winters to thrive.

Caryopteris odorata
The largest of the Caryopteris, it forms a shrub, reaching a maximum size of 13 x 13 feet ( usually about half that ), and is native to the Himalayas at elevations up to 7000 feet.
The short-stalked, entire to toothed, pointed leaves, up to 5 inches in length, are green.
The blue-violet flowers are borne during late summer.
Hardy zones 6 to 9

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