How To Propagate Hardy Geraniums
Whether it's to increase the number of cranesbills in your own garden, or to give away to friends and family, propagating hardy geraniums is fun, rewarding and delightfully easy to do.
There are a few different techniques you can use to propagate cranesbills, some of which are suited to particular species, so we’ll run through some of the most useful, starting with the most common method: division.
As most hardy geraniums are clump-forming division is often the most practical method way to propagate them. It’s easy and generally fail-safe. G. clarkei, G. ibericum, G. x oxonianum, G. nodosum, G. phaeum, G. pratense, G. sylvaticum, and G. versicolor all work well using division.
Dividing geraniums can be done once the foliage has died back during the dormant period – from autumn right through to spring.
Not only will division provide you with more plants but it will also help to refresh and revitalise the vigour of your plants. In fact, whether or not you’re propagating it’s a good idea to lift and divide clumps every 3-5 years for this reason – a task that can be applied to many other herbaceous perennials too.
Dig up the clump and knock off any excess soil.
Use a sharp spade to cut through the roots and then a pruning saw or knife to cut into smaller clumps. Some pieces can be pulled apart by hand.
Divide each clump as much as you like.
Replant the divisions where they are to grow or pot them up.
Using a spade, cut around the clump.
Lift up the clump and use the sharp edge of the spade to cut through the clump and divide.
Use a pruning saw or knife to cut the clump into smaller pieces.
A divided piece ready to be replanted or potted up.
A more traditional method of dividing the clump is by plunging two garden forks back to back into the centre and then pulling the handles apart, using leverage to force the roots apart.
But I generally find that dividing with a saw and/or knife gets the job done just as well.
Whichever way you choose, you should find dividing your plants a very successful and productive way of propagating them.
Dividing clumps can be potted up, placed somewhere sheltered, and planted up in early summer.
Geranium species such as G. pratense, G. sanguineum, G. versicolor, G. maderense and G. argentum can all be grown successfully from seed. Cultivars in general will not, and usually rely on vegetative methods such as those below.
But seed sowing from cultivars can be fun; provided you like surprises! For instance when sowing the cultivar G. pratense Striatum (Splish Splash) the usually white and blue flecked flowers can either be all blue, all white, or a mixture just like the cultivar!
After collecting seed and storing it dry throughout the spring and summer (paper envelopes or bags are ideal – never plastic), the autumn months can be a good time to sow. The following March or April provides another good opportunity to sow seeds.
Sow in pots or trays of gritty compost and cover with a thin (0.5cm) layer of fine, sandy compost mix. Water from below by standing in a tray of water and place in a bright spot avoiding direct sunlight. Germination can be expected from 2- 4 weeks, though often after much longer periods too – so don’t give up!
Add gritty compost to small pots (7 to 9cm are ideal) and using a dibber or pencil create 5 to 7 holes into which you can then insert the pieces (top uppermost). Insert deep enough so that the top of each root is level with the compost, and then cover with a thin layer of horticultural grit. Water the pots and label, before storing in a cold frame, greenhouse or a sheltered spot. There’ll be perfectly fine in the winter cold, but a bit of shelter will protect them from the worst of the elements such as heavy rain.
Once roots appear through the drainage holes the cuttings are ready to be split up and planted into individual pots.
It’s also possible to lay the root cuttings horizontally on top of the surface of the compost.
Using pots or trays filled with gritty compost, lay the pieces horizontally on top of the compost. Ensure they make good contact with the compost by pressing them in firmly and cover with grit
Many of the alpine species tend to make good candidates for stem cutting propagation. Works well for Geranium ‘Bertie Crûg’, G. cinereum, G. farrei.
Stem cuttings can be taken anytime during the growing period. The best time of day to take stem cuttings is early morning. Using a sharp knife cut off a few healthy stems and cut into 3-6cm pieces, each one just below a node. Remove any flowers or seed pods, and leave only 2 or 3 leaves on each piece of stem.
Using a pencil or dibber insert the cuttings into pots of gritty compost and place in a greenhouse, cold frame and avoid direct sunlight.
After germination seedlings can be pricked out into a gritty, peat-free compost once the first true leaves have developed. When a good root system has developed the plants will be ready for planting out. Most cranesbills flower a year after germination, though some species like pratense will take 2 years before flowering for the first time. By the third year plants will be mature and should go on to provide you with many years of enjoyment.
Geranium sanguineum, in all its forms, lends itself perfectly to propagation by root cuttings, as does G. psilostemon and its many cultivars.
Dig up the plant or lift it out of its pot to expose the roots, and break off a few of the long, white chunky roots closest to the crown, about pencil thickness: these should make ideal cuttings. You should be able to feel the nodules along the root, which is from where new shoots will begin to form.
Using a sharp knife cut the roots into 4-5cm lengths. You’ll want to keep the root the same way up as the parent plant so lay them out in front of you with this mind. Or you can simply cut the top end straight across and the bottom end slanted so you can easily tell which way the root should be.
Use a sharp knife to cut into
Keep the root the same way up as the parent plant, so note the top and bottom.
Root pieces ready for potting.
Insert the root vertically so the top of the root is level with the compost.