Every border seems to develop the odd bare patch sooner or later, whether from a plant that failed to establish or simply from gaps left when everything was first planted. Rather than leaving that space to be taken over by whatever weed happens to blow in, a quick-spreading plant can fill it in convincingly within a single season.
Plants that spread readily by their own runners or self-seeding are particularly useful here, since they need very little encouragement once settled. A small division taken from elsewhere in the garden, or a handful of self-sown seedlings gathered from beneath an established plant, is often enough to get such a gap filler going without any additional cost.
Choosing the right spreader for the spot
It is worth matching the vigour of the chosen plant to the size of the gap, since a particularly enthusiastic spreader can quickly overwhelm a small space and start crowding out its neighbours. A gap tucked between two well-established shrubs calls for something rather more restrained than an open patch with plenty of room to expand.
Light and soil conditions in the gap matter just as much as they would for any other planting decision. A shrinking violet of a plant that prefers rich, moist soil will struggle in a dry, sunny gap, however eager it might otherwise be to spread, so it is worth observing the spot for a while before choosing what to put there.
Filled with the right plant, a gap that once looked like an eyesore can become one of the liveliest parts of the whole border within a year. Keeping half an eye on how far the new plant is spreading ensures it fills its intended space nicely, without quietly creeping on to claim territory meant for something else entirely.
Checking back on the gap every so often during its first season helps catch any early signs of the new plant either struggling or spreading rather more enthusiastically than intended. A little trimming back at the edges keeps its enthusiasm in proportion with the rest of the border, without undoing the effort of filling the gap in the first place.
