Filling in the gaps

Whenever I plan a planting scheme for a garden, I always try to remember the little hidden places where plants can grow, in the gaps and cracks in walls and paving and steps, and various other places normally ignored or forgotten. When plants want to grow in unusual places in your garden it is a thing to be encouraged.

Tiny plants growing in gaps in paving can provide a welcome contrast to acres of stone by adding splashes of green and softening up hard edges and corners. These are all the better if they are self-seeders, sending their offspring plants to other corners of the garden, sometimes in surprising ways. Obviously this type of planting needs an element of control or the garden would quickly become an unruly mess, so its worth pulling out anything which is either in the way or making a nuisance of itself in some way.

There are many plants which lend themselves well to this type of growing, not least Oxalis corniculata atropupurea or creeping wood sorrel, which self-seeds like mad and works very well in paving cracks. It goes a bit mad so worth keeping an eye out but with its purple leaves and bright yellow flowers it is a welcome nuisance!

A great favourite of mine is the Mexican Daisy, Erigeron karvinskianus.
This friendly little plant, looks like a common or garden daisy except that it is able to creep down the sides of stone walls and steps and tuck itself into crevices, where it both seeds and spreads using its rhizomatous roots. It is a native of Mexico but can be found in many dry gardens in Britain.

It needs plenty of sun as well as good drainage in order to survive cold wet winters. Easily raised from seed, it can be mixed with a small amount of clay and pressed into chipped out mortar joints in walls or mixed with a little compost and scattered into the cracks between paving stones.

It’s also worth thinking laterally with planting in this way because the plants don’t always have to be small and mounded. Consider taller softer plants such as Verbena bonariensis or Dierama pulcherrimum; also know as angel’s fishing rods. Both of these are beautifully soft and tall and won’t block the view, but will certainly add some unusual interest in paving gaps. Slightly smaller at 15cm is the lovely Sisyrinchium angustifolium or blue-eyed grass, which was born to grow in cracks in the paving. Not actually a grass at all but a primitive variety of Iris, the amazing blue flowers do not open wide until lunchtime.

The more imposing Campanula lactiflora or milky bellflower with it’s panicles of violet-blue bells in summer can also seed themselves anywhere they can get a hold. Pinching out the lead shoots early on in their growth to prevent them getting too leggy and tall can control them. They are so pretty that they are also worth the bother of a bit of staking and keeping an eye on!

There are so many plants which are worth trying to grow from seed in unusual places, it’s interesting to experiment, but where to begin? The first thing to do is to clear out the space you are thinking of planting into, making sure there are no perennial weeds or couch grass tucked away, if necessary give the spot a squirt of systemic weed-killer if necessary, or ideally run a tool such as a screwdriver or blunt knife around the space to make as open a space as possible and remove any small roots. Mix your seeds with some seed compost, John Innes is perfect for this job and then brush the mixture into the hole using a dry paint brush and then water using the finest watering can rose you have so as not to wash the mix immediately out of it’s space.

This method is often more successful than trying to get established plants to take, but if you do have wider spaces in your paving or walls, particularly dry-stone walls, or you are planning to have paving laid, then consider leaving out some smaller areas to allow for planting pockets. Try planting mound-forming thymes such as Thymus serpyllum ‘Magic Carpet’. This will spread over the edges of the paving creating a lovely green area, which will release its scent if trodden on.

Another perfect plant for walls and cracks is Sempervivum or house- leek. These are succulent alpine plants, which usually grow in the wild in mountainous regions. They need very little in the way of compost or soil but they do need good drainage, so be sure to plant these with a layer of grit on top of the soil as well as mixing in grit to the compost where they are being planted. I love these plants as they can survive very well through winter and in summer will send out crazy looking flowers.

If a neat, tidy or regimented garden is not for you, and it’s certainly not my style of gardening, then take a look around your garden for small nooks to grow some of these lovely plants.