Monday, May 30, 2016

Dividing Primroses

There are many types of primroses from the simple cowslip to those with specific growing conditions, such as the "candelabra" that need constant moisture, or the auricula, another thing altogether.

I grow some of these, but this post is about the more "common" plants belonging to the  genus Primula.

Primula are deceptive as they give the impression of being rather sturdy plants, but they are not.

In Old Fashioned Flowers  Sacheverall Sitwell says:  "There could be no greater mistake than to imagine they are capable of looking after themselves."

Here is how I take care of the primulas pictured below. I entitled this post "Dividing Primroses" because the big job is to divide them in spring.

A assembly of primulas

In Wood and Garden, the redoubtable late nineteenth century English gardener,  Gertrude Jekyll explains that she spent "a day or two" dividing her primroses which were replanted in a bed that had been "dug over and well manured".

She had a boy to help her and two men to do the digging, manuring and replanting.  What I find interesting about that story is the leisurely pace it suggests. How much would you get done with two men and one boy in two days? More than the primula beds I would bet.

However most of us, not being able to count on a boy, let alone on a couple of men or even on actual manure, have to make do with a simpler approach.

Primula are shade plants that prefer a woodsy soil, one with ideally a lot of leaf mold. If you can provide these two requirements, shade and good soil, you have a much greater chance that they will thrive for you.

Primula "Guinevere" perhaps my nicest - pale pink with leaves that open purple

I try to divide mine about every second year. Ideally I would do it only when they have finished blooming, but because I want to make sure which is which when I replant them, I divide them when there are still a few blooms.

Once they are lifted, I pot them up by colour. They do not all divide the same way.

For instance, with the two shown below, Guinevere divides beautifully. All divisions have plenty of roots. The Cowichan red (first photo below) does not divide well. Even if you are careful, many of the divisions end up with hardly any or no roots.

The medium I used to pot them is almost entirely made up of compost. As a rule, primroses are not happy in containers, but I pot them up for a week or so before I replant them, because once in pot it is easier to make sure they are well watered and doing well before being replanted.

The rich potting soil, which surrounds the root when they are replanted, is my attempt at mimicking Miss Jekyll's two nineteenth century men manuring.

Sometimes I break my own rules, as I did this year, for instance. After they had been potted up for only 3 days we had a downpour, and so I replanted them the moment the rain had stopped.

Red Cowichan - the petals of that flower seem to be made of velvet
You have to keep an eye on them. The moment you take them for granted, they quickly disappear.

I use to have a collection of various double ones, and they all have vanished, except for this white one you could call semidouble.

To end with, the way NOT to use primroses.

Used in bedding-out schemes, like below, these polyanthus provide a fair bit of colour, but most of the primrose charm is lost.


  1. I love primroses, but have mixed success with them. The drumstick ones did well last year, but were practically a no-show this spring. I have a red one (must look up the cultivar name) that I just love and it does very well. This spring I will muster the courage to divide it.

    1. It is funny I had the very same experience. The drumstick (denticulata) did well last year but this spring I was down to one single plant. I suppose they did not like the winter even if it was a mild one. The coldest April on record might be the culprit.

  2. You have reminded me that I have quite a few that need dividing, especially my doubles, they have dwindled to just a double blue, so I must do it soon.

    1. I would like to get some double again. I might order seeds from Barnhaven as I am unlikely to find some in nurseries around here.

  3. Thanks for a very interesting and informative post Alain. I had just assumed that primroses are quite tough, and would survive and prosper with very little care. I have lost some doubles, and now I understand why!

    1. Some are tougher than others. Guinevere, which is probably my favorite, also happens to be my toughest primrose.

  4. I did not know that Primulas required such dedicated dividing. This is one of my least favorite garden chores. I admire Primulas, but I'm not sure I want them in my garden.

    1. Different strokes for different folks! I would say you can get away with not dividing for 3 years or so, but they soon start to disappear.

  5. Good advice Alain and interesting post. I liked you collection of primroses. I usually divide them by hands, it's very easy. And I do this in August when they finish to flower.

  6. I have lots of primula vulgaris - our native primrose - which must be an exception to this rule. It is left to get on with it as it would in the wild. I end up with loads of self sown seedlings every year too. The plants seem very happy.


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