Plant of the Month for July, 2012

 (a-KANTH-us hun-GAR-ee-kus)

General Information:

The first time I saw Acanthus hungaricus in flower I was mesmerized. This is such a spectacular architectural plant that it should be in every garden. 

Acanthus hungaricus; photo by Robert Pavlis

Acanthus hungaricus is an erect clump forming perennial with pale pink to white flowers enclosed in a spiny reddish-purple bract. The flowers open slowly from the bottom to the top. As the flowers fade, the bracts remain on the plants and slowly turn brown providing a long floral display. The leaves are slightly glossy, deeply lobed and up to  2 feet long. Even out of flower this is a great looking plant.

My first plant was a fairly small seedling and after 2 years in a sunny dry spot it had still not flowered. I bought 2 more and planted them in part shade with more moisture, one quite wet. They did not flower either. Suddenly, they all flowered. A. hungaricus takes a few years to settle in and get large enough to flower. It does not seem to be fussy about its growing conditions. After 5 years, the first seedling had 20 flower spikes.

Acanthus hungaricus; photo by Robert Pavlis

Acanthus is a genus of about 30 species, native to warm temperate regions. The common name is bear’s breeches. A. hungaricus is also called Hungarian bear’s breeches. There are three common species grown; A. spinosus, A. mollis and A. hungaricus (aka A. balcanicus). All three are very similar and frequently misnamed. The three species have also been crossed forming plants with intermediate characteristics. A mollis has shinier leaves which are less deeply lobed and the outside edges of the lobes are rounded. The flowers tend to be a creamy white or pink. A. spinosus and A. hungaricus have very similar leaves; both are very deeply lobed, but the outside edges come to a point.  A. spinosus  has rigid spines on the edge of the leaves and it has whiter flowers. A. hungaricus has no spines on the leaves. If you are growing the plant in zone 5 or colder, it is not A. mollis which is reported to be hardy only to zone 7.

Life Cycle: perennial

Height: plant is 60 cm (2 ft) and flowers add another 60 cm

Bloom Time: mid summer

Natural Range: Balkans, Romania, Greece

Habitat: dry, open rocky slopes, usually on limestone; field margins, fallow and waste ground.

Synonyms: A. balcanus, A. longifolius

Cultivation:

Light: full sun or part shade                              

Soil: normal, well draining soil, tolerates a wide range, pH 5.8 – 7.5

Water: drought tolerant once established, but prefers regular watering                     

USDA Hardiness Zone:  5 – 10

Propagation: root cuttings or seed  

Seedex availability (ORG&HPS annual Seed Exchange): available regularly

E

Sow @ 20°C for 6 weeks, then place @ 4°C for 6 weeks, then slowly raise temperature to 10°C for 6 weeks. If there is no germination, repeat the cycle. This mimics fall sowing outdoors for spring germination.

7

Requires soaking. Place in warm water until seeds swell, usually 24-48 hours. Discard floaters and the water used for soaking. See https://youtu.be/dhL57pqnHHQ
Robert Pavlis