CALTHA palustris

Product 699 From 3785

CALTHA palustris

Kingcup, Marsh Marigold, May-Blob, Meadow Bright, Souci d'eau
Select Item No. CO044

Also available as:


One Portion is usually sufficient for approx. 50 plants.
Please switch to gram for larger quantities.

Plant Description

Article Type: (Organic Seed DE-ÖKO-006)
Life Cycle: Perennial
Family: Ranunculaceae
Origin: Northern Hemisphere
Distinction: Award of Garden Merit (A.G.M.) from the Royal Horticultural Society.
Special Features: The beloved flowers - the color of butter - and the glossy green heart-shaped leaves, once used in salads by early settlers in the USA. A plant perfectly suited for stream banks or at the edge of pools. Plant of the Year 1999 in Germany.
Historical: Pliny and Virgil commonly used the name Caltha for yellow flowers, possibly for Caltha palustris. Palustris indicates that it is from moist areas.
Basic Colour: (yellow / gold)
Flower Colour: deep yellow
Natural Flowering Period: April - May
Winter Hardiness Zones: Z3 - Z7
Foliage: heart-shaped, shiny green, toothed margins
Growth Habit: clumping
Height with Flowers: 30 cm
Spacing between Plants: 30 cm
Soil Requirements: boggy
Characteristics: medicinal plant
Usage: honey-bee food plant
Grams per 1000 seeds: 0.71429 Gram
Seeds per Gram
(does not correspond to the number of plants!):
Gram to get 1000 plants
(if sown directly into pots etc. you will need a larger quantity):
4 Gram
Plug tray recommended size(s): open flats
Sowing Direction:

(2) Most species of the Ranunculus-family need lower temperatures during the cooling-period – about –5°C [23°F]. In other respects follow the directions in 1. above. The reason is probably the freezing point of these seeds, which is at –7°C [19°F], while most other seeds freeze at –5°C [23°F].

(1) Cold-germinators are still referred to as frost-germinators, although this isn’t quite correct. The sowing must be kept warm (about +18 to +22°C) [about 64 to 72°F] and moist for the first 2–4 weeks. After this period the sowing must be kept at a cold temperature (between –4 and +4°C) [between 25 and 39°F] for another 4–6 weeks. Colder temperatures of –5°C [23°F] are only advantageous for most species of the Ranunculus family. It is not so important if the temperature is higher or lower during the cooling period, but the cooling period has to be prolonged because the synthesis of the germination inducer, hormon-like acid, slows down or comes to a standstill.
It is beneficial to cover the sowing with snow during the cooling-period. The temperature below it usually keeps in the optimum range of –4 to 0°C [25 to 32°F]. The sowing is kept moist, and the melting snow helps to destroy the shell, which is advantageous for the germinating seedling. After this cooling-period the sowing may not be immediately exposed to high temperatures. The most effective temperatures are between +5 to +12°C [41 to 54°F], even if germination has started. The best location for this sowing, even in March, April and May, is the open field, the cold frame or a cold greenhouse.

(3) These species usually show excellent results if sown soon after the harvest, although most of them only germinate in spring after the effect of winter. For best results please order seeds in time.

(18) See 17. Allow the seed trays to be left for only 2–4 weeks at warm temperatures, then keep at 0°C [32°F] for another 4–6 weeks. It does not matter if the water freezes. After this treatment allow temperature to rise gradually.

(17) Waterplants must be sown in waterproof plastic trays or similar containers containing a nutritious muddy compost. Fill water up to 1 cm over the top of the compost. Keep the trays at warm temperatures of approximately +22°C [72°F].

Sowing to Germination: 10 - 12 weeks
Germination to Transplant: 4 - 8 weeks
Transplanting to Potting: 6 - 10 weeks
Cutting back at Transplanting: Not Necessary.
Container Size(s): 1 plug per 8/9 cm (3 1/2") / 1-2 plugs per 11/12 cm (4 1/2")
Vernalization: There is no current research on vernalization but a prudent recommendation for any perennial would be 6-12 weeks (a few might need 15 weeks!) at an average daily temperature of 40°F (5°C). Exposure to cold may not be necessary for flowering but might improve quality.
Forcing: An obvious place to experiment - following vernalization - would be raising daytime temperatures to 60° - 65°F (15° - 17°C). Provide 16 hours of continuous lighting. During the short days of winter, provide a night interruption lighting of 4 hours between 10:00 p.m. and 2:00 a.m.
Fertilizer: Medium (150-200 ppm)
Jelitto · Seeds of more than 3700 different species and varieties


*: excl. TAX, excl. shipping