So many people are bewildered by the term Herbaceous Perennial, so here’s an explanation: Perennials are plants that live for at least three years and usually longer; Herbaceous means soft, non woody growth that dies back to the root each winter and grows back in the spring. But in the garden a herbaceous perennial is more than just a leafy plant, the majority are grown for their attractive flowers which usually appear for a few weeks of glorious colour, any time from later winter to early autumn.
Herbaceous borders. Because the flowering season of perennial is quite brief, they are usually grown in long, straight beds amongst lots of other varieties that flower at different times of the year to give continuous flower throughout the growing season. In late spring and summer , there are so many perennials in flower that the herbaceous border is alive with colour, as well as pollinating insects such as bees. To see an example of a proper herbaceous border, visit large gardens such as those at stately homes, Royal Horticultural Society gardens, and botanical gardens, where each perennial is planted in large numbers. It’s easy however to recreate this on a smaller scale at home, just make sure to pick your perennials so that there is always something in flower from March to October. Planting in threes (or fives if you have ) gives a better effect than planting singly, producing large clumps.
You don’t need to devote a whole border to perennials, they also look great intermingled with shrubs, roses and dwarf conifers in a mixed border. This is better for small gardens or borders overlooked by windows, as the season of interest is longer, and there’s always something to look at, whereas a purely herbaceous border will be almost bare in the winter. You can even plant perennials in a large patio container; just make certain that you choose those that will be happy with their roots constricted, that won’t get too big and that they get their required amount of light or shade – check the individual label
Recommended perennials by month of interest.
- March: Helleborus; Primula; Bergenia.
- April: Caltha; Doronicum; Euphorbia; Pulmonaria; Primula.
- May: Aquilegia; Dicentra; Nepeta; Paeonia; Papaver.
- June: Astrantia; Delphinium; Dianthus; Geranium; Geum; Lupin; Veronica.
- July: Achillea; Alstroemeria; Campanula; Coreopsis; Erigeron; Gaillardia; Hemerocallis; Heuchera; Monarda; Penstemon; Polemonium; Scabiosa; Sidalcea; Verbascum.
- August: Agapanthus; Crocosmia; Echinacea; Helenium; Helianthus; Hosta; Kniphofia; Phlox; Rudbeckia; Salvia; Stokesia.
- September - October: Anemone, Aster; Lythrum; Sedum;
Dividing. Perennials spread, making clumps bigger and bigger until the centre of the plant dies out. To keep perennials healthy and to increase your stock, divide the plants every few years where needed. Summer flowering plants can be divided either autumn or early spring, whereas spring flowering perennials are best divided in summer once flowering is finished.
Plants to divide should not be putting on growth at the time. Lift the plant from the ground with a garden fork, then either tease apart by hand if the roots are or with well-developed fibrous root systems put 2 forks in back to back, pulling apart gently. Some plants may require the use of a spade or knife to separate. Plant or pot all divisions immediately, and keep watered until established.
