Propagating plants through division is a simple technique, but one of the most valuable garden ideas to keep it well stocked and in good shape. It will also help to ensure your planting scheme looks cohesive and natural by repeating favorite plants. It is better to create a well-considered garden color scheme rather than a rainbow of different varieties. ‘You can increase your stock of clump-forming plants – including perennials, spreading shrubs, underground rhizomes, bulbs and tubers – by dividing them every two or three years,’ says Period Living’s gardening expert Leigh Clapp. Dividing plants in this way also keeps many varieties in better health, as it reduces congestion, helping them to stay vigorous. Indeed, some plants become unproductive after a few years if you do not divide them. This technique also improves the plants’ appearance, as on many perennials the original center can die away as they grow outwards, leaving an unsightly gap. ‘It will take a little time for the new plants to establish, but you will cut costs and replicate the specific variety,’ adds Clapp.
How to divide plants – the essentials
Dividing plants involves separating small rooted sections, or clumps, of the plant – or its miniature offshoots, bulbs or tubers. You then replant them, and most will successfully grow on to become strong individual plants. Every plant has its own preferred methods of propagation. Certain plants, such as annual flowers, are best grown from seed – essential when planning a cut flower garden. Others will root well from cuttings – for example, knowing how to take rose cuttings is an invaluable skill for every gardener. However, propagating by dividing – or splitting – is an easy and effective way to multiply many clump-forming plants including:
Herbaceous perennials – the staples of most gardens, these are the non-woody perennials that die away at the end of the season, but then come back each year, as their underground root system lies healthy and dormant below ground. Popular herbaceous perennials include geraniums, delphiniums, lupins, peonies, rudbeckias, salvias, hostas, and many ornamental grasses.Clump-forming evergreen perennials – many of these are still herbaceous, but don’t fully die back, retaining some or all of their leaves. This group includes hellebores and heucheras.Bulbs and tubers – this group includes spring bulbs that produce ‘baby’ offsets, such as tulips and daffodils, as well as summer bulbs, such as alliums, agapanthus and lilies. Dahlias are the most notable flowering plants with tubers, though there are a few others, such as certain orchids. Other ‘bulb’ plants with corms, such as freesias, and rhizomes, such as irises, can also be propagated through division.Many succulents – including aloe, sedums and sempervivum.
How to divide perennials
Perennials are some of the most populous plants, and will likely make up a significant proportion of your flower bed ideas. According to the Royal Horticultural Society (opens in new tab), perennials can be divided successfully at almost any time of year as long as they are kept well-watered afterwards. However, to ensure success, it’s best to do it when the plants are dormant. Summer-flowering perennials are best divided in the fall, before the harsh winter weather sets in, or from the beginning of spring, when the garden is showing signs of new life. But don’t allow the new shoots to become too big. Spring-flowering perennials, however, are best divided in the summer, once they have faded and begun to grow new roots. Focus your attention on those that have spread out a lot and are becoming congested, rather than smaller, newer plants. ‘You can tell which ones you need to attend to by the large clumps that are pushing outwards from the ground with fresh young shoots at the edge of the clump,’ says plantswoman Sarah Raven (opens in new tab).
How to divide bulbs
Many bulb flowers will multiply their numbers by growing new ‘baby’ bulbs off the parent bulbs. These can be easily separated and turned into new plants. In fact, if you don’t divide bulbs, you may find that they will become congested and not flower as well after a few years – in particular tulips. So if you do notice them becoming less productive, think about dividing them. Other ‘bulb’ plants that grow from corms or rhizomes can also be separated in a similar fashion. ‘You can divide rhizomes, such as iris and canna, after flowering,’ says Clapp. ‘Trim back the foliage, lift, remove any dead pieces from the rhizome, divide, and replant.’
How to divide dahlia tubers
Dahlias require special consideration when it comes to dividing them, as they have tuberous roots. An important aspect of learning how to grow dahlias is knowing how to overwinter the tubers. A popular method is to remove and store them, as the frost can be fatal, and this is the ideal time to divide them.
How to divide succulents
‘Succulents are particularly easy to propagate through division, as clump-forming varieties produce offsets,’ says Clapp. There are many different types of succulents, so if you find you are unable to easily divide sections from your plant, the good news is that many varieties also propagate very well from cuttings.
On many succulents, you can simply remove soil from around the base of the plant, then prise away sections, offshoots, or ‘baby plants’.If the roots don’t separate easily, then you can cut through these, and they will recover.Plant the new succulents straight into the ground, or in a pot filled with well drained potting mix, ideally containing perlite.‘You can also take leaf cuttings from fleshy leaves species, and stem cuttings from branching types,’ adds Clapp. Fleshy leaves can break away very easily and quickly grow their own roots.
When can you divide plants?
You can divide plants at almost any time of year. However, it’s usually best to do so when they are in a state of dormancy, but not during periods of severe weather. Spring is the ideal time to divide many perennials.
Can you split most plants?
It’s possible to split many plants, but not all. Some plants will need to be propagated through growing from seed or cuttings. Generally, most herbaceous perennials and bulb flowers can be split – or divided – and grow on as new plants.
