Geraniums Will Look Better Later In The Season If They’re Given A ‘Chelsea Chop’
Elizabeth is a Permaculture Garden Designer, Sustainability Consultant and Professional Writer, working as an advocate for positive change. She graduated from the University of St. Andrews with an MA in English and Philosophy and obtained a Diploma in Applied Permaculture Design from the Permaculture Association.
Reviewed By ROY NICOL
Roy is a Professional Gardener and Horticultural Consultant, specialising in large garden year-round maintenance and garden development. He is an RHS Master of Horticulture and uses his research in the application of no-dig methods in ornamental garden settings. Roy has been a Professional Gardener for more than six years and is a member of the Chartered Institute of Horticulture, Professional Gardener's Guild and Association of Professional Landscapers (Professional Gardener).
Contributions From GARY CARROLL
Gary is the Owner of Cranesbill Nursery. He worked as a Gardener at the five star ‘Sails in the Desert’ hotel at Ayer’s Rock Resort in the outback and as a Gardener at the 17th Century National Trust property, Moseley Old Hall.
Geraniums, both tender geraniums (Pelargoniums) and hardy geraniums, can be relatively easy and trouble-free plants to grow.
The hardy types especially can be great low-maintenance plants for a garden.
However, there are some jobs that it is important not to neglect, and pruning is one of them.
| Difficulty | Moderate |
| Equipment Required | Secateurs |
| When To Prune | Varies by type |
According to expert Horticulturist Colin Skelly: “many hardy geraniums, particularly taller or flop-prone species and cultivars, will look better later in the season if given a ‘Chelsea chop’ – so-called because it is typically carried out in May around the flower show time.
“Following the first flush of growth, cut back by one-third to one-half.
“This will ensure a tidier plant and flowers into late summer.”
That being said, how you prune geraniums will depend on which type you are growing, and, if growing tender types, how you plan to overwinter them.
Here are the basic rules to follow:
- Prune Pelargoniums which have been overwintered as bare-root dormant plants back to around 10cm in spring.
- Prune Pelargonium overwintered in pots, which will be kept in a dormant state to 10cm in autumn.
- Prune Pelargonium overwintered in pots and kept in active growth in autumn (cutting back by one-third to one-half) – or hold back until spring.
- Pinch back growing tips of Pelargonium to encourage bushy growth on new or overwintered plants. Take a centimetre or two off every stem.
- Cut hardy geraniums back after they have finished flowering. Cut back to just above ground level to rejuvenate a plant that is becoming woody or straggly. Otherwise, cut back by around one-third as required.
Pruning Pelargonium (Tender Geraniums)
When you should prune Pelargoniums depends largely on how you have (or plan to) overwinter them.
Remember, these are plants which cannot survive the winter outdoors in our climate.
Pelargoniums can be kept for more than one year, if you do not wish to dispose of them at the end of the season by:
- Taking cuttings in summer. (If you take cuttings, you may then dispose of the parent plant, and each of the cuttings will grow into a clone of the parent.)
- Overwintering bare-root as dormant plants.
- Overwintering in pots, in a dormant state.
- Overwintering in pots, in active growth.
The pruning time and the extent to which the plants are cut back will depend on which of these options you have chosen.
If you decide, at the end of the growing season, that you would like to keep your Pelargoniums in a dormant state in pots, then you should cut back the plants to around 10cm above the surface of the growing medium in autumn, when you bring them into a frost-free location.
You might also prune in autumn if you plan on keeping your plants in pots in active growth.
Remove any yellowing or browning leaves and any straggly growth, and, if the plant looks a bit leggy, you can also consider cutting back stems by around one-third to one-half.
However, this may not be necessary and you may wait until spring.
Pelargonium which are overwintered as bare-root plants should typically be cut back to 10cm in spring.
Regardless of which option you have chosen, with most Pelargonium it is also a good idea to pinch off the growing tips after fresh new growth emerges in spring.
This simply means nipping or snipping off the top 1-2cm from all the stems just above a leaf node.
Where the tips have been pinched off, this will encourage new branching to occur, which leads to a bushier and fuller plant.
Pruning Hardy Geraniums
Hardy geraniums are low maintenance and don’t always need much pruning at all.
But it can be a good idea to keep them healthy and prevent straggly or woody plants by pruning back by around one-third after they have finished flowering, as Gary Carroll, owner of Cranesbill Nursery, explains:
“Most hardy geraniums will benefit from being cut hard back halfway through the season.
“They will then bounce back with fresh foliage and, usually, a second flush of flowers.
“The plant will tend to give you a hint when to do this, as it will start to look a bit tired, and the flowers might diminish.”
If a plant is not looking as good, you can hard prune back to just above the ground to give your plants a new lease of life.
However, be aware that not every geranium variety can cope with hard pruning.
“The two main types that are a bit different as regards cutting back, are the G. x cantabrigienses and macrorrhizums,” says Gary.
“These can be cut back, but they have thick stems from which the foliage sprouts, which you shouldn’t cut into, as these stems form the [main] structure of the plant.”
