(ass-PLEE-nee-um try-KOH-man-ees)

General Information:

A perfect rock garden plant, and by rock garden I mean growing right on top of rocks. Asplenium trichomanesis a great little evergreen fern that likes some shade, and can grow with virtually no soil. It is quite happy growing in a small crack in a stone. They will also grow in the ground if given a very porous soil.

Several Asplenium trichomanes growing on a giant limestone bolder in Aspen Grove Gardens; photo by Robert Pavlis

Asplenium trichomanes, the maidenhair spleenwort, grows naturally all over the world and is quite common in Ontario. There are several subspecies, but taxonomists are still sorting some of them out. Three subspecies are commonly accepted. Ssp. trichomanes is a diploid and grows on acidic rocks such as sandstone and granite. Ssp. quadrivalens is tetraploid and grows on alkaline rocks like limestone and can grow in the mortar of walls. The difference in growing conditions between the diploid and tetraploid is quite unusual considering that each contains essentially the same DNA. There is also a hexaploid, ssp maderense, which is found only in Australia and New Zealand.  

Asplenium trichomanes; photo by Robert Pavlis

A. t. ssp. quadrivalens is stouter and has more pinnae which are squarer in shape than A. t. ssp. trichomanes. It’s fronds grow closer to the rock and old fronds that have lost their pinnae fall off. A. t. ssp. Trichomanes fronds grow more vertical, and persist after the pinnae fall off. Both species are found in Ontario.

Ferns do not flower in the traditional sense, so they never make seeds. They can however be propagated by growing the spores they make. These are found on the underneath side of the fronds in a special structure called a sori. More information for propagating ferns from spores can be found at http://www.hardyferns.org/fern-info-propagation.php

Asplenium trichomanes sori; photo source Wikipedia

Life Cycle: perennial

Height: 15cm (6 inches)

Bloom Time: does not bloom

Natural Range: worldwide

Habitat: mossy rocks in part to full shade

Synonyms:  Asplenium melanocaulon, Chamaefilix trichomanes

Cultivation:

Light: part to full shade

Soil: very well drained

Water: drought tolerant

USDA Hardiness Zone: 2– 9

Propagation: spores, division

Seedex availability (ORG&HPS annual Seed Exchange): rarely

Do you want to encourage Monarch butterflies, but hesitate to grow our native perennial milkweed because of its invasive roots? Jean Gardiner brought this great alternative to our attention and provided the following description.

Asclepias curassavica is native to southern Florida, therefore, acts as an annual in Ontario gardens and so is not invasive. While it is an introduced species, the plant is so similar botanically to our native milkweed that it attracts and provides excellent food for Monarch butterflies and their larvae.

Asclepias curassavica  Common names: Mexican Butterfly Weed, Bright Wings, Tropical Milkweed

Diana Pooke, ORG&HPS member                                          

This milkweed is charmingly different from our native Asclepias syriaca having brilliant red, yellow or orange coloured flowers that bloomed from August until frost in our garden. The two to three-foot plant is similar to most milkweeds with opposite leaves, a milky sap and characteristic flowers. However, in addition to more brilliant colours, A. currassavica has narrow lanceolate leaves and the banana-shaped pods are much narrower than our native milkweed but contain the species parachute-like seeds. It is easy to grow in full sun to partial shade in almost any soil condition. It is a proven Monarch butterfly magnet, and also is reputed to be attractive to hummingbirds. Dr. Clement Kent of York University showed slides of his wildflower garden to the Toronto Master Gardeners. His red milkweed plants were smothered with dozens and dozens of Monarch butterflies.

There will be seed in the ORGS &HPS Seedex of the yellow cultivar. If the weather stays warm there may also be seed of the red variety. Sow the seeds indoors about 6 weeks before the last frost. They will germinate in about one to two weeks at room temperature.

We'll try to have some seedlings available at the Super Plant Sale on May 6, 2012

Thanks go to Jean Gardiner, Diana Pooke and Rob of www.robsplants.com for their help this month.

 (air-uh-see-muh  thun-BERG-ee-eye)

General Information:

Arisaema thunbergii ssp. urashima is a great aroid that adds some excitement to the garden. Known as the dominatrix jack-in-the-pulpit it appears in late spring and is gone by late summer. Its special feature is a long, dark purple, whip-like spadix that can reach 45 cm long, in true dominatrix fashion.

Arisaema thunbergii ssp. urashima by Robert Pavlis

Unlike many of its cousins, this denizen of the woods is easy to grow. Over time it makes offshoots that can be separated from the parent plant. It can also be grown from seed but may take 3-5 years to flower.

Fertilized flowers will produce red berries that mature in fall after the leaves have faded. All parts of the plant contain calcium oxalate and are poisonous.

Arisaema thunbergii ssp. urashima by Robert Pavlis

The subspecies urashima, is similar to the species, but is shorter growing to just 45 cm tall, and has 11-15 broad leaflets instead of 9-17 narrow ones.

Arisaema thunbergii ssp. urashima by Robert Pavlis

Arisaema thunbergii ssp. urashima by Robert Pavlis

Life Cycle: perennial

Height: 45cm (18in)

Bloom Time: late spring

Natural Range: Japan

Habitat: woodlands

Synonyms:  Arisaema urashima, Arisaema thnbergii, Flagellarisaema urashima,

Cultivation:

Light: part shade to shade

Soil: humus-rich, well drained

Water: medium to wet

USDA Hardiness Zone: 5 - 9

Propagation: seed, division

Seedex availability (ORG&HPS annual Seed Exchange): rarely

 (air-uh-SEE-muh  si-ko-kee-AH-num)

General Information:

If you think Jack-in-the-pulpits are plain looking you have not seen this queen of the arisaems, Arisaema sikokianum. One look and you will desire her.

Arisaema sikokianum:photo by Robert Pavlis

As a member of the aroid family this flower has a white protruding sex organ called a spadix, surrounded by a dark purple pitcher, the spathe. The white spadix glows in a shady garden and can be spotted from quite a distance. The plant will be shorter with smaller leaves in more light and larger in heavier shade. A. sikokianum is one of the first arisaemas to flower – late May in zone 5. By mid-summer it will have gone back underground. If you are lucky, the seed head will continue to ripen until fall, producing spectacular read berries.

This plant is also known as the circumcised Japanese Jack-in-the-pulpit, the Japanese cobra lily, the Japanese dragon arum and my favourite, the gaudy Jack. The flower is single-sexed but it can change its sex from year to year. Both sexes need to be present in order to form seeds and it will cross pollinate with closely related species.

Arisaema sikokianum:photo by Robert Pavlis

Unlike many arisaema, this one rarely produces offsets. The best way to propagate it is from seed which takes 3-4 years to flower. Seed germinates fairly easily at room temperatures.

Life Cycle: perennial

Height: 45cm (1.5ft)

Bloom Time: spring

Natural Range: Japan, China

Habitat: woodland edges

Synonyms:  Arisaema sazensoo, Arisaema mafnificum, Arum sazensoo

Cultivation:

Light: part shade

Soil: moist but well drained

Water: medium to wet

USDA Hardiness Zone: 4– 9

Propagation: seed, seldom produces offsets

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