ASK DIARMUID

Q

I’m thinking of planting some herbaceous plants this autumn. I am tempted to stuff the border to get a full effect next year. How much empty space should there be in a newly planted border? Alan, via email

A

That’s a great question! There’s no hard and fast rule but I would leave around a foot between each plant, which will give them space to develop. They will put on a lot of growth in spring and blend together, forming a good cover to exclude weed growth beneath. You can be more technical about this and look up each plant and check what size and width it will grow to.

The great thing about herbaceous plants is that as they mature and perhaps become overcrowded, you can always lift them in spring or autumn and change around the planting scheme.