Perennials: Plants that come up and flower each year are known as perennials. Trees and shrubs grow and flower every year too. But they are known as woody perennials, as opposed to non-woody perennial flowers.

Growing from seed

A very easy and inexpensive way to grow new kinds of perennial flowers is to raise your own plants from seeds. While most perennial flowers are normally propagated by division, many can be raised quite easily from seeds. This is a very good way to raise new vigorous plants, usually less troubled by diseases and pests than those raised by division, the latter tending to carry their problems with them.

Apart from the obvious saving of money involved in raising plants from seeds, it is possible to raise large numbers of new plants fairly quickly. Many kinds of perennials will flower the following year and under good conditions, some of them will even flower the same year as small plants, even from a June sowing.

Traditional sowing outdoors

Traditionally, perennial flowers were sown in open-ground seed beds, at least the more robust kinds. This is still a perfectly good way to raise many perennials, although sowing seeds in trays is a more dependable way since they do not have to deal with the more challenging conditions of the open ground outdoors. Many kinds can be sown outdoors in a well-prepared fine seed bed. Examples include geum, lupin, alyssum, carnation, delphinium, foxglove, heuchera, dimorphotheca, erigeron, gaillardia, achillea, hollyhocks, evening primrose, aquilegia, coreopsis, aubrieta, rudbeckia and centranthus.

If sowing in the open ground, make a raised seedbed, about one metre wide by shovelling up the soil from a drill on either side. Use the extra soil to make a deep, fine seed bed. Cover the seeds with clean sand. Sow the seeds thinly and make sure to keep weeds down.

Most perennial flowers are remarkably vigorous. If too many young plants come up, thin them out or lift them and transplant them at a suitable spacing, which might vary from 15cm2 to 30cm2 on a new nursery bed. Water immediately and each day until growth resumes. Allow the young plants to grow on until late autumn or early next spring before lifting and planting out in their final quarters.

Sowing in trays

The seeds of perennial flowers can also be raised in trays in a greenhouse or cold frame. Some of the finer kinds can be raised in this way.

Generally, plants with small seeds need the tray treatment whereas the larger seed kinds are fine in the outdoors bed. The seed companies have recognized that there is potential in perennial flowers and they now offer a much wider range of flower seeds.

Another source of seeds is simply to collect them in the garden or in other gardens — with permission, of course. Many garden flowers set good seeds and these can be sown right away, or stored in paper envelopes in a cool place and sown next year in spring or summer. The seeds are ready for collecting when the seed pod splits and the seeds are turned brown or black usually.

There is also the thrill of possibly raising a new variety and this happens surprisingly often with garden-collected seeds.

Very many garden varieties throw up variants very frequently. Often these are no better than the parent but occasionally they are.

If you have not sown perennial flowers before, why not begin in a small way? CL

Sow parsley now


If you have had trouble with getting parsley to grow, try sowing it now. The main reason for failure with parsley is sowing too early. If it is sowed too early in the year when soil temperature levels are below its requirements, the seeds are likely to rot. In summer, the soil will be well warmed up and the parsley seeds will germinate very reliably. Be sure to use fresh seeds, not old packets that have been knocking around for a couple of years. Sow in fine, well-tilled soil in a sunny spot. A fairly light, not overly fertile soil is ideal. Too rich a soil makes for very lush leaves that tend to be soft and lack flavour.

Things to do this week

Trees, shrubs and roses

Young trees and shrubs need to be checked regularly for signs of drought. Sometimes the rain does not penetrate a dry root ball and the plant can still suffer badly. Continue to tie in the new shoots of climbing roses so that they will be in the correct position for training later.


Although late, better late than never — bedding plants can still be planted, and containers and baskets planted up. There is still plenty of time for them to give value, especially if large plants in individual pots or cell trays are used. Be sure to control the first flush of weeds among bedding.


Despite cold weather earlier in the year, it has been a good year so far for grass growth and lawns have looked well. There were bouts of rain and if it was possible to get on a shake of fertiliser, the effect is quickly visible and the grass will benefit enormously during the next few weeks.

Greenhouse and house plants

Use a greenhouse shading material now if the house is inclined to get too hot. Continue to feed greenhouse plants every two weeks to get good growth before midsummer and continue to water well. Control pests such as greenflies. Display flowering greenhouse and house plants.

Fruit, vegetables and herbs

Finish off the sowing of maincrop vegetables such as carrots, broccoli and peas. Repeat sowings of those sown early, such as lettuce and peas, could be made. Thin out vegetables that have reached suitable size, and control weeds early. Weed growth is strong at the moment after rain.