Crocus care tips for March
Why grow perennial flowers from seed?
Few gardeners make the most of the wide range of perennials that can be grown from seed. Verbascums, aquilegias, coreopsis rudbeckias and penstemons are easy to grow in this way and not only will they will give your garden a colour boost, they will also help you save money.
It is a common misconception that perennials take several years to come into flower from seed, but many of them, including coreopsis, lupins and penstemon, will flower well in their first year provided they are sown early enough.
The seeds of perennial plants tend to be relatively cheap because they are generally older varieties that don’t command the premium prices that the new F1 and F2 hybrids can. And you can expect to raise dozens of sturdy plants from a single packet. Raising your own plants from seed is very satisfying, but you can also save a great deal of money along the way provided you can use a lot of the same plants and choose the right varieties. Bear in mind that named varieties don’t always turn out the same as the parent plant, so if you experiment you may have to weed out the rogues as they appear. There are two main reasons for raising your own perennial flowers from seed:
- To save money This is particularly true if you need a lot of plants of the same variety for an extended bedding scheme or for use as groundcover. Many are excellent sellers at charity stalls and school fairs too, raising lots of money for next to no outlay. Also, if you want to create a traditional cottage garden, then the range of varieties on offer is ideal for providing the bulk of the planting. Some perennials, such as lupins and verbascums, are short lived and need replacing on a regular basis, which can become prohibitively expensive if you are on a tight budget. And yet if you buy a packet of seed, not only can you raise plants cheaply, but a single packet will give sufficient supplies for many years provided you can store it correctly – for instance in a light-excluding foil packet in an air-tight container at the bottom of a fridge.
- To get better results A few perennials, including aquilegia, are difficult to root from cuttings or division and so are easier to grow from seed. Others, like hollyhocks and some chrysanthemums, are healthier if seed-raised because diseases are not carried on from one generation to the next via the seed itself. Often these varieties are more difficult to find as plants because nurseryman are unable to keep their stock plants healthy. Some perennials, including sea-holly (eryngium) and alstroemeria resent root disturbance. This means they do not divide well and suffer a severe setback when they are planted out as rooted cuttings. By sowing them direct into their flowering positions you can easily avoid these problems.
But there are drawbacks to raising your own perennial flowers from seed. The most obvious is that it takes more time and effort and if you only want a few plants of a particular variety you may not save much money. A few perennials, including delphiniums, can be tricky to raise from seed, while others such as granny’s bonnet (aquilegia) and sea-holly germinate erratically. A few perennials are slow to get going – some hellebores, for example, can take three or four years before they flower. You’ll also be unable to grow many of the better new varieties because they are simply not available as seed. But if you want an adventure then get sowing!
Sowing methods
The easiest way to sow most perennials is direct, which means outside in a seedbed or in the border in their final flowering position. You will usually get better results however sowing in pots or trays, potting up the resulting seedlings and planting out as sturdy plants. This is the best method with tricky varieties that have tiny seeds, or which germinate erratically, or take a long time to germinate. Don’t be impatient. Because perennials generally take longer to germinate than annuals you may not see anything emerging for a month or more, then, up they will come in a rash. Seedlings from outdoor sowings will need thinning to achieve the correct spacing – any good-quality seedlings can be used to fill gaps or transplanted to flower elsewhere in the garden. You can also grow them in a row on the vegetable patch for their first year, setting them out about 20-30cm apart in the row and between rows. Then, in autumn, they can be transplanted to their ultimate flowering position.
Fast-track perennials
To get plants of flowering size in the first year you will have to start them early. Sow them now in 10cm pots or half-sized seed trays filled with fresh seed sowing compost, then place them in a heated propagator set at 10-15oC (50-60oF). Pot them up individually as soon as they are large enough to handle safely. Place the resulting plants in a cool greenhouse or cold frame, or under cloches in a sheltered part of the garden. The plants can then be planted out into well-prepared soil during late April or early May.
Perennials to sow now
(to flower this year): baby’s breath (Gypsophila paniculata); bellflower (Campanula persicifolia); coreopsis (Coreopsis grandiflora); cupid’s dart (Catananche caerulea); hollyhock (Alcaea rosea); lupin (Lupinus polyphyllus - look for single colours); penstemon (Penstemon x gloxinioides) and yarrow (Achillea millefolium or A. filipendula, but not hybrids).
Perennials to sow by the end of March
bears breech (Acanthus mollis); delphinium (such as ‘Dwarf Pacific Mixed’); heuchera (Heuchera sanguinea); incarvillea (Incarvillea delavayi); peruvian lily (Alstroemeria – look for ‘Ligtu Hybrids’); and maltese cross (Lychnis chalcedonica).
Perennials to sow by the end of April
anchusa (Anchusa azurea); blanket flower (Gaillardia aristata); blazing star (Liatris spicata); columbine (Aquilegia vulgaris, look for the ‘McKana Hybids’); fleabane (Erigeron speciosus); geum (Geum chiloense); globe thistle (Echinops ritro); granny’s bonnet (Aquilegia vulgaris); purple mullein (Verbascum phoeniceum); sea-holly (Eryngium); and shasta daisy (Chrysanthemum maximum).
