Making the Most of Perennials

With summer waning and autumn on our doorstep it’ll soon become the time when dead heading turns into cutting back. This season, herbaceous plants appear to be dying back sooner than usual.

Crocosmia 'Lucifer' after division. Aberglasney's Sunken Garden

The flowers in Aberglasney’s borders have mostly finished for the year leaving the Dahlias shining bright as the main attraction. In the perennial borders, especially the woodland ones, many of the plants are turning brown and beginning to flag ready for winter. In many ways, this is the most exciting part of the season as we begin to plan and prepare for any changes we need to make to the garden for next year. Invariably, there are always plants that have gotten a little too big or have maybe outstayed their welcome.

Division usually happens in late summer or autumn. The literature will tell you to do it after flowering, but honestly, any time in the winter is fine. It’s a great garden practice as it allows you to revitalise old clumps, create new space, and most importantly creates spare plants. I personally prefer planting divided plants (or bare roots as they are often called) as they’re peat-free, create no plastic pot waste, have been lifted/moved at the right time, but most importantly; they are excellent value for money.

Dividing Plants with Two Forks

Most herbaceous perennials are propagated by division. It’s easy to do with most plants but there are some exceptions, such as Peonies. The simplest way is to lift the clump, lever it apart with two forks and split it into two. This process can then be repeated until numerous smaller clumps have been created. Next, remove the old dead material (usually in the middle of the clump) and replant the young vigorous pieces. Most perennials will benefit from this being done every 3 – 6 years depending on how fast they grow.

Young, healthy divided corms of Crocosmia Lucifer

There are different division methods for different plants, but the principle always remains the same. After replanting there will be plenty of spares left over which can either be planted elsewhere in the garden or gifted to a friend. If you choose to do this, however, always be very careful not to transport weed – especially the nastier types such as couch grass, bind weed or ground elder. Any material containing weeds should be thrown or carefully picked through. I tend to go for the safer option and throw them away. If you find you have perennials with stubborn weeds like couch grass growing in them then division is a great way to remove it.  

We’re dividing the perennial garden at Aberglasney this autumn. It’s a huge job but it’ll allow us to redo the borders and reduce those thugs to make room for some less vigorous plants. So far, we’ve found that the first clumps of Crocosmia ‘Lucifer’ have produced hundreds of spare bare root plants. These are being given to our volunteers and sold in the shop over the winter period. 

Division produces good quality home grown plants that area fifth of the price of pot grown ones, plus there’s no waste. It’s easy to do in a home garden and will produce many spare plants that you can swap/gift. They make excellent Christmas presents for gardening friends!

Tips for the Week: 

1. Choose plants that need division 
2. Cut back the perennials that are going over 
3. Keep picking fruit and veg 
4. Keep watering and feeding tomatoes - they can fruit until November indoors 
5. If the weather is dry, dig out and dig over ground with spent vegetables 
6. Remove and compost as much dead material as possible 
7. Burn diseased material around the garden to reduce disease problems