Read about Craig Presnell

Always on the lookout for something different, Craig introduces . . .

Three Unusual and Interesting
New Marginal Plants

by Craig Presnell
Zolfo Springs, Florida USA

Click images to enlarge

Acanthus ebracteatus (Holly Mangrove, Jeruju hitam) is an unusual plant with dark green spiny leaves that, at first glance, bear a remarkable resemblance to American Holly (Ilex opaca). 
A tropical species originating in southeast Asia, this plant reaches a height of about 1.5 m (4.5') and forms dense thickets. Like a mangrove, it develops prop roots, but those of Acanthus are small. It will grow equally well in full sun or shade, but the leaves of shaded plants are flat, rather than ruffled, and they do not develop the sharp spines of those grown in the full sun. White flowers are borne in spikes and produce pods with spring dehiscence and are capable of propelling the seed distances up to 2 m (6') when ripe.
It is tropical, so winter protection is necessary in zones colder than USDA 10-11. Planted around the perimeter of a water garden, it is sure to provide a painful deterrent to pilfering or damage by rogue animals.  

Crinum oliganthum is a dwarf Crinum from the West Indies. While mature leaves are generally less than 3 cm (7") long, this plant spreads by runners and will form clumps up to 1 m (36") wide. It will grow in full sun, but is also useful as a ground cover under taller plants.

Perhaps the best feature of this plant is the disproportionately large fragrant flower it produces. The six petalled white flower that is a miniature of that seen on C. americanum can be 5 cm (2").

Despite its Caribbean origin, C. oliganthum is hardy to USDA zone 8b. It thrives in constantly moist conditions, but is also extremely drought tolerant. C. oliganthum can be a versatile addition as an accent in a water garden or a main player in a container garden. 

Gunnera perpensa (River Pumpkin) is a dwarf Gunnera from tropical east Africa. The leaves of River Pumpkin . . . and I’m assuming the name comes from the leaf shape . . . may only grow to a height of 0.5 m (18"), but forms a beautiful cluster from a creeping rhizome that looks quite a bit like a Petasites. It is a vigorous grower but not invasive. Flowers are borne on a spike that extends above the leaves that has female flowers at the base, bisexual flowers mid-spike and male flowers at the top.

Perhaps the most exciting aspect of this plant is that there is finally a Gunnera that is heat tolerant and can survive in a much broader area of the US than the cool, moist conditions required by the South American Gunnera now offered. Even though it is heat tolerant, to survive it requires heavy shade and constant moisture. It did survive last year’s summer temperatures in Florida without heroic efforts and is hardy to USDA zone 8 without protection  

WGI ONLINE Journal Table of Contents

Water Gardeners International
Home | Join WGI | Members' Exclusive | Gateway to Water Gardening