Plant of the Month for December, 2019

 (KAL-tha  pal-US-triss)

General Information:

Caltha palustris may be a common plant but each spring it becomes a star in the garden for about 3 weeks. It has been in my garden for over 10 years, never gets any maintenance, never has pest or disease problems and it flowers like crazy. How many garden plants can match these qualities?

 

Caltha palustris: photo by Robert Pavlis

Caltha palustris:photo by Robert Pavlis

The marsh marigold likes to sit in water, or at least have wet soil in spring. If things get too hot or dry in late summer it will die back. It is perfectly suited to the shallow edge of a pond or waterfall as shown in these pictures. It is such a great plant that the Royal Horticulture Society has given it their prestigious Award of Garden Merit (AGM).

Other common names include kingcup, mayflower, May blobs, mollyblobs, pollyblobs, horse blob, water blob, water bubles, gollins, and publican. Although it is called a marigold, it belongs to the buttercup family is unrelated to the aster family.

Caltha palustris: photo by Robert Pavlis

Caltha palustris:photo by Robert Pavlis

If the plain, single yellow one is too common for you to grow, it is also available as Caltha palustris var. alba and Caltha palustris ‘Floro Pleno’, a double form.

Caltha palustris: photo by Robert Pavlis

Caltha palustris:photo by Robert Pavlis

Life Cycle: perennial

Height: 25cm (10in)

Bloom Time: spring

Natural Range: Northern temperate regions

Habitat: sunny pond edges, river banks and ditches

Synonyms:  NA

 

Cultivation:

Light: sun to part shade in hotter climates

Soil: variable

Water: wet to standing water

USDA Hardiness Zone: 3 11

Propagation: seed, division

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

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This species needs special care as described.

5

Germination is successful only when GA3 is used. See http://botanicallyinclined.org/fridays-seeds-with-the-ga3-seeds-treatment

L

Give sown seeds several weeks @ 20°C to imbibe water (perhaps even germinate!), then expose to fluctuating outdoor winter temperatures including freezing for 3 months. Gradually increase light and temperature in spring. See https://www.youtube.com/watch?v=SO_KKbGYTEM

hydrophilic, sow as soon as seed is ripe; will not germinate if seed has dried; for storage put in plastic bag with barely damp vermiculite; keep them warm during summer, coolish towards the fall and then 4⁰C at the onset of winter. Do not store them in the freezer because the formation of ice crystals will damage cell membranes; bog plant; stand pot in 3 cm water; raise temperature very slowly after germination
Robert Pavlis