How to raise Windowsill Primroses
OPTION 1 - Raising your own from seed
a. Order seed in late June or early July (try Stokes Seeds in the US, Jelitto or Chiltern in Europe - the all ship to the US. There are other sources, but you will need to search for them.
b. Sow seed in flats in late July. Do not cover seed, but protect from birds, heavy rain and full sun.
c. Grow on with care 'til frost - Once seed is sprouted, water careful as to not hurt the seedlings, and transplant into individual pots when seedlings have 2 pairs of leaves, which will be around mid - Sept.
d. Bring indoors before a hard freeze, or place in a greenhouse. Indoor plants will do best in a garage window, an unheated room that does not freeze, a cellar window or a sunny, cool window in the house.
e. Provide only natural light, as artificial light will confuse the plants into thinking that it is summer. They will need short day lengths to set bud.
f. By January, you should have flower buds, and the plants can now take full sun in a cool window.
Buy plants in bloom at your local market! I won't tell anyone.
|One can have dozens of winter blooming primroses, but it takes some planning. I begin in July by ordering seed, which isn't as easy as one may think, but try Harris Seeds here in the US, or Chiltern Seeds which will ship to the US from England. A late July seeding is needed for a mid winter crop, which is when these plants bloom.|
|Seeds are sown in July, along with pansies and other biennials for early spring blooms. You don't need a fancy greenhouse, but you will need a very bright cold window for the winter months, or light set up -- but be careful about one key factor - day length, for these are plants that will only form buds once the days are short ( I don't know that specific hours required - but mine set buds around the New Year so take your cues from nature. Longer nights are key.|
|The seedlings are tiny at first, and they grow slowly until cool weather arrives around October, which is when I transplant them into 3 or 4 inch pots. In the greenhouse, they really take off in November, which is when I feed them well with a low nitrogen fertilizer to help stimulate flower formation, which should happen around Christmas time.|
|Primula malacoides seedlings beginning to blossom in the greenhouse a couple of weeks ago. If I fertilized them more, they would have been larger. If I offered bottom heat, even larger.|
Primula seed is generally quite tiny, tiny as in poppyseed tiny, or even smaller, so one must proceed carefully wearing both the hats of a skilled botanist and that of a talented crop manager when it comes to sowing such small seed. I use the classic method of mixing the seed with dry sand, or vermiculite (silver sand), which helps in distributing the seed evenly on the surface of the flat. I use a sterilized plastic seed flat, with sterilized potting mix in it, as primula are very prone to damping off, even when started outdoors, as after all, it is still August here in New England, and thus, it is hot and humid.
|This year, I have grown this wild form of Primula malacoides - which today is putting on quite a show in the greenhouse. Plants that I gave away as house gifts in January are actually doing better than the ones in the greenhouse. This is one primrose that really likes to never dry out, even though it doesn't want to sit in water, it should go partially dry first, and then be watered.|
You may noticed that these primroses look a little different than what you typtically see at the market, right? But look - we've all fallen for those bright colored low growing primroses one often seen at the super market, but I wanted to share with you some more these more growable ones, and encourage you to try them if you seed them ( usually, they are only a couple of dollars each, so they are not a huge investment). Yes, they are highly attractive to both aphids and white fly, so be wary of that, but consider them disposable winter color -- a spa in a pot, if you will. We all need a little 'spa treatment' by late winter, and especially in this one, right?
|Look what bloomed today! A rarer primrose, the unusual Primula x kewensis, a natural occurring hybrid of Primula verticillata, makes a great windowsill plant, if you can find them. This species is easy enough to raise from seed if you are a capable seed raiser. If not, then search for them at your garden center this spring, as I know of at least one wholesaler who distributed these along with garden primroses last year ( it will not grow well outside).|
There are some other indoor primroses, like the Primula x Kewensis above ( the yellow one), which is terribly difficult to find, but it is perhaps the best primrose to grow as a house plant. I first grew mine when I was editor for the American Primrose Society Journal, a task I took on rather reluctantly, when I first joined the society in 2001, but it was the best way to learn more about growing primulaceae. Primula x Kewensis came to my house as a small seedling, and I soon fell in love. You can get seed from the seed exchange if you join the American Primrose Society, or you can look online, as there are a very few sources. As I mentioned in the caption, I did find some at a garden center in the spring last year, as one distributor last year ( Sunny Borders) grew a crop for some crazy reason -- maybe just to excite me. So you never know. It is easily identifiable because of its white powder ( farina) on the foliage.
|Primula obconica, still in bloom in the greenhouse. This winter blooming primrose has lightly fragrant flowers that come in basically the same color palette as those candy hearts with saying one gets at Valentines Day (except yellow). This periwinkle and citron version, if my fav. I have grown this selections for 30 years - ever since I was in highschool, really. It just says 'winterspring' to me. Really. Winterspring. I just made that up.|
Most of these winter blooming primroses are from Asia, and although they have been hybridized by the potted plant industry into many interesting selections which are sometimes found at local greenhouses if you are a good plant hunter. The most common primrose sold as houseplants will continue to be the polyanthus types which we all see in bright violet, saffron yellow, brilliant pink and scolding red, with a little rosette of leaves. Yep - - those little African Violet looking type of primroses again, and I needn't warn you about their watering issues - for if you blink, they die from lack of water, never to return again. They provide needed color in early January, but are honestly a waste of money in comparison to any of these primroses mentioned here.
|Primula obconica dissappeared from the trade for about 20 years because the foliage caused a contact dermatitis ( not uncommon with all primula for people who are sensative to primulin, the chemical in most primula) but this species was particularly irritative. Modern varieties have been bred to have a reduced amount of both primulin, and the micro hairs on the foliage that used to irritate the skin.|
I know that I've been over-sharing many of my primrose images of both these seed raised winter blooming types, as well as some of those P. obconica that I purchased at my local market. You should know that each of these winter blooming primroses are far more resilient than those typical sort one sees with bright, low growing flowers in purple, yellow and red, but don't ever think that any primrose is carefree- the all require attention, for they never wish dry out completely. Just, slightly. Ever....so...slightly. Keep them on your coldest windowsill, and as March progresses, watch the sunshine, as they will burn as the sun brightens. Yes....I promise, it will brighten.
|If you ever are lucky enough to find a Primula x kewensis, buy one and keep it on your window ledge for late winter and spring cheer. The foliage is covered with white farina, which will be nicer when grown inside. In my greenhouse, the hose washed it off every time I water. But the mossy pot sure looks sweet!|