I had a letter recently from Keith, who lives at Horndean, telling me that nearly all his herbaceous plants flower for about three weeks and then just the foliage remains.
He says he has overcome this problem by choosing plants such as hostas, ladies’ mantle and rogersia because the foliage looks wonderful on all of those plants.
He also uses irises alongside each of them as the foliage then contrasts. What he would like, however, is a border with flowers all summer. What would I suggest, he asks?
First of all, I do admire his ideas and a lot of landscape designers do exactly the same things. This can often be seen in show gardens such as we see at Chelsea Flower Show and Hampton Court Flower Show.
All the gardens look brilliant just for the period of the show, but after a short time the colour has disappeared, there are no flowers left to enjoy and the bees and butterflies will have to go elsewhere to get nectar and pollen.
It is possible to add plants to a border of perennials by adding some annuals. These are sown from seeds in February in the greenhouse and planted out at this time of year.
One of the finest is called salpiglosis, a glorious annual about 18 inches tall with flowers almost the same as petunias. But the flowers are striped with rich blue, mauve and yellow stripes and patches.
This plant is rarely seen these days, yet it is more glamorous than an orchid.
My favourite is cosmos, also known as Cosmea. It is important to ensure the eventual height of the plant is understood, because plants range in size from about one foot to three feet.
In our border at home we have a scattering of them so that there are blooms every day from now right up until the frosts arrive.
Cosmea are available in pots at garden centres. They are in bloom now so the right colours can be chosen. They will be tall and are simply knocked out of the pots and planted in between the herbaceous perennials.
I didn’t see a Cosmea in any of the show gardens at Chelsea Flower Show. It must be because none of the garden designers read my articles!
Or perhaps it’s because Cosmea is so cheap to buy!
My final suggestion is dahlias. The single blooms grown from seeds are the cheapest, costing between 25p and 75p per pot .These single flowers are full of pollen and nectar, so the bees and butterflies love them.
The heights vary and the plants flower well all summer as long as the dead blooms are picked off regularly.
They are very good for arranging indoors too. If you can get hold of a dahlia catalogue there are literally hundreds of varieties, ranging from the tiny pom poms right up to blooms as large as dinner plates.