Cultivation (growing techniques): Sanguinaria canadensis
Started by: John Humphries
A little background to a favourite plant. Please add your comments and photographsGo to latest contribution by Giles Reed, 20 May 2009, 09:05. Go to bottom of this page.
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Named after the carmine-coloured juice in its rhizomes and roots. Sanguinaria is a single species genus from eastern North America. The red sap contains a toxic alkaloid, sanguinarine, capable of causing many side effects including nerve poisoning, if taken internally, so you should always wash your hands after handling the rhizomes. However the sap is combined with oak bark to make a natural red dye.
The leaves and flowering stem arise from the rhizome around March in early spring. The flower is initially concealed, wrapped within the emerging leaves, but quickly expands above them as they unfurl.
This is truly a woodland ephemeral as all too often the weather contrives to destroy the beautiful white bloom in the first day. However given some shelter or favourable conditions outside and the blooms can last 4-8 days each with a succession of single flowers providing a month?s interest on an established clump. The rounded leaves are pale green and 4?8 inches broad, with shallow or more deeply cut, wavy lobes. These leaves remain green for most of the growing season and provide sufficient interest in their own right to guarantee the plant a place in any garden I will ever have. The flowers themselves can have anything from 6-12 white daisylike petals surrounding the many yellow central stamens. There appear to be several forms including semi double and fully double varieties.
The latter appear to be sterile with stamenoid petals, although they often tease you with a seed capsule which is always empty. On the singles glossy brown 1/8th inch seeds will be found within the fruit. These have a crest called a "caruncle". It will be no surprise to learn that this is the prize that ants, the dispersal agents, gain for carrying them off, later chewing off the caruncle and burying the seed. This also provides a clue to the planting depth for seed as they are not surface sown by the wind but rather buried ½ an inch deep. Coming from eastern North America, they are reliably hardy to ?30C, providing us with a clue to good germination, as cold as possible for 2-3 months.
Bloodroots thrive in good rich, moist soil with full sun in early spring during their main flowering and growing season. Here they will rapidly form large clumps and form a very attractive ground cover. Although they grow best when the pH is 5?7, ample humus and moisture are more important. The soil should be well drained but retain moisture, they are often found growing in the sides but not the bottoms of ditches.
Bloodroots propagate easily from both rhizome divisions and seed if sown very fresh. As seed is only rarely available, and then is usually not fresh, division seems the easy option. Split the rhizomes either in the late summer when the leaves have just withered or just before the plant comes into growth. Remember to wash your hands, or wear gloves when handling the roots.
This was a plant given to me by a friend recently when renewing a portion of his garden, the root clump had already had 24 pieces broken off to give to other members of the local group as part of the plant raffle in October.
Plant sections of root bearing one or more buds horizontally about an inch deep with the buds near the soil surface. Plants from rhizome divisions often flower the following spring.
I have had good success with splitting plants when dormant, and can report a 100% failure on the one occasion I split a large clump just after flowering, although this may well have been due to keeping the divisions too moist.
I put all the odd sections with little or no buds into a fishbox, in the hope that(like Trillium) some dormant buds will be forced into life with the absence of a growing tip. I'll report back on that in April.
Propagation from seed appears quite easy when freshly ripe seeds are collected from the fruits as they split open in the mid- to late spring. The seeds will germinate best if kept moist and given a cold treatment for 2?3 months over winter. Seedlings can be transplanted the following summer but will take about 3 years to flower. I have not yet had success with old seed which has dried out.
I've had very little success with seed even from my own plants but obviously they've not been cold enough. What is ripening now, I plan to sow and water then put in the deep freeze until about the end of February then let them have a "normal"winter which here, is down to about -3 degs C.
I echo Lesley's thanks, John. What an excellent intro to this plant. We too have found that division when dormant is the safest method of increase. I have been charmed by a pink Sanguinaria, which I was shown photos of by the Doctors Bainbridge, but I cannot recall where in the wild it was growing. Does anyone know more about the very lovely pink variety? It was single flowered. Lesley, hello, nice to see you getting out and about here, too!
I recently won the above plant at the Fritillaria Group Raffle. Could anyone please tell me anything about this cultivar, ie) is it single / double, white / pink, or variations in habit to the species. Many thanks
Chris, Sorry about the delayed reply, I'm fairly sure that it is a single flushed with pink.
The next few weeks should see its emergence, if it is the one I'm thinking of it is faintly veined pink on the outside and very softly coloured on the inside.
Sorry about the quality of the image, it is the only one I could find of my plant, the foliage is also slightly darker initially, fading to the normal green.
There are lots of other variants around I I would be very happy for anyone to add to this thread with their plants whether nearly the same or distinct.
Here's a nice little plant just emerging now.
I do not have a name for it as it is different from the slightly flushed pink form above in that this one is pinker about the foliage.
Also on one of the images above, I showed a collection of old bits of root with no buds on them.
Happily I put these in an old fishbox and tucked them away.
Here you can see I have a dozen or so new shoots and flowers from what were supposedly dead roots.
The received and observed wisdom on these plants seems to be that you should move them on and divide them every 3-4 years.
Perhaps the reason why these are so expensive in the nurseries despite being relatively easy to propagate is that they do appear to get a root rot after a few years in the same location.
Remember though, never split them while in active growth, after they have gone dormant or just before they come into growth.
I've had seed of the singles germinate but never managed to grow them on. Has anyone else had success??