Post category: Flowers
Hardy annuals are raised from seed sown in seed trays or directly in the ground where the plants are to flower. They can be sown in March, April or May. March sowings can be affected by cold, wet weather. May sowings can be affected by dry conditions and, anyway, they tend to flower late. Early April is usually a good time.
Seeds of some types can be sown in September, too. These over-winter as young plants and flower earlier the following summer than the spring sowings.
Dig the ground, working in general fertiliser at 70 grams per square metre. Break up all lumps and rake the surface fine. Some peat or organic material might be worked in too if the soil is poor. Make little drills with a stick about 15 centimetres apart and 1 centimetre deep. Sow the seed thinly and cover with soil.
If the area being sown is larger than about 1 square metre divide the space into areas of about this size and sow a few different types. Seed can be sown broadly scattered about too, but sowing in lines makes it easier to distinguish flower seedlings from weeds.
Hardy annuals grow best in good, fertile, but not over-rich soil in full sunshine. Some kinds, such as California poppy and pot marigold, can tolerate poor, dry soil.
When the rows of seedlings can be distinguished, lightly run a hoe between them to kill weed seedlings. Weeds should never be allowed to get established. Watch for slugs and snails, too. When the seedlings are about 2 centimetres high, a first thinning can be carried out, though, if the seeds were sown thinly enough, this will not be necessary.
When the seedlings are 5 centimetres high, they can be thinned to their final spacing. This varies from 5 to 10 centimetres apart for small kinds to 30 centimetres apart for large types. If there are gaps, they can be filled by lifting and transplanting excess seedlings carefully.
Some of the taller types may flop about when grown on good soil. Bushy twigs might be used for support. Hardy annuals often self-seed, so areas of the garden might be set aside for this to occur.
Flowers that germinate, grow and flower in one growing season are called annuals. Some of these tolerate frost and they can be sown outdoors – these are hardy annuals. Annuals that cannot tolerate frost must be sown indoors and planted out when the danger of frost has passed – these are half-hardy bedding annuals.
Cosmos for quick summer colour
Some of the flowers used for bedding, such as bedding busy lizzies, bedding begonias and bedding geraniums, are actually short-lived perennials but they are treated as annuals, raised from seed each year and discarded at the end of the season. Some flowers, such as wallflowers, bachelors buttons and pansies, are sown in one growing season and flower the following year.
Plants that flower each year, and then die down over winter are called perennial flowers. The taller types – from 30 centimetres to 300 centimetres – are used as border perennial flowers. Those that grow to less than about 30 centimetres are used as rock garden or front of border perennials.
Bulbous flowers with bulbs, tubers or corms, are a special category of perennial flowers, and deserve special mention.
Root-rot disease and damping-off sometimes occur if plants are over-watered as seedlings or, later, as plants. The roots die and rot sets in. Avoid over-watering and injury during pricking-out. Use clean trays and compost.
Monarda destroyed by powdery mildew
Virus diseases attack many perennial flowers and bulbs, causing mottling or streaking of the foliage, stunting and reduced flowering. Affected plants should be destroyed. Leaf spot diseases of various types sometimes cause red or brown spots on the leaves of many flowers. These are rarely serious.
Powdery mildew attacks some flowers, especially michaelmas daisies and monarda. Spraying is not worthwhile and if the trouble is persistent, grow something else.
Slugs and snails are the most serious pests of flower plants of all types. Most damage is done in late spring and early summer to young plants and new shoots, especially susceptible plants such as hosta and ligularia. Precautions will often be necessary.
Greenflies cause curling and stunting of foliage, and pass on virus diseases. Control may be necessary. Caterpillars of various types eat holes in the leaves of many flower plants. Unless the damage is extensive, which is unusual, control is not necessary.
Capsid bugs are little beetles that eat the very young leaves as they push out of the ‘bud’. Dahlias and annual asters are especially vulnerable. Earwigs and woodlice are usually responsible for ‘mystery’ damage to foliage and flowers. No pest can be found because feeding is often nocturnal.
Leatherjackets, vine weevils and cutworms are soil inhabitants that attack the flower plant roots or stems at ground level. Eelworm are microscopic pests of flowers. If plants are stunted, ‘bloated’ in the stem, or fail to flower, eelworm may be the cause.
Included here are bulbous plants with corms such as gladiolis, tubers such as begonias, rhizomes such as cannas and true bulbs – all types of storage organ. Plants in this group find many uses. Bulbs are ideal for use with spring and summer bedding plants, and they are lovely in pots with spring bedding plants, or on their own. They can also be used to bring colour to herbaceous and mixed borders in spring, summer and autumn. Certain bulbs can be used in semi-wild conditions – ‘naturalised’ under trees or shrubs, in grass or ground cover.
Bulbs are usually raised as offsets from the mother bulb, and will, in three or four years, grow to flowering size. Many types can be grown from seed too, taking about the same length of time to flower.
Bulbs need well drained, fairly rich soil, particularly tulips and gladiolus. Plenty of organic material is important to open the soil and allow air to reach the bulbs. Water-logging rots most kinds of bulbs, so avoid damp spots, except for a few that like damp ground, such as cammasia, snakeshead fritillary and leucojum.
Plant the spring-flowering types in October and the summer and autumn-flowering types, such as dahlias and gladiolus in spring/early summer. As a general rule, plant bulbs at a depth equal to twice their height. This helps to support the stems.
For naturalising, plant the bulbs at random, but not too far apart. Simply lift the sod and pop the bulbs in. Bulbs in pots or bowls can be potted up in early September for flowering at Christmas. These should be kept in a cool, dark place indoors, or buried outdoors – bowl and all – until early November when they are brought into a warm room to flower.
Tender bulbs such as dahlias, gladiolus and begonias, lifted and stored from year to year, can be started into growth in March in a greenhouse or a warm sunny window sill in trays or pots of moist compost. Alternatively, plant them out to their flowering positions, unsprouted, in late April.
Aftercare for bulbs
Bulbs generally need little attention but keep them reasonably weed-free for best results. Some fertiliser, every few years, helps to maintain flowering. Frost-prone plants, such as dahlia, begonia and gladiolus, will have to be lifted in autumn and stored indoors for the winter. They might be risked outdoors by covering them with a layer of peat or ashes.
Bulbs naturalised in grass must not have their foliage mown off until it goes yellow and begins to die. This is usually in late June and a lawn may look very ragged by then. It is best to naturalise bulbs in lawn areas that would not be conspicuously untidy if left unmown, such as under trees. Otherwise, naturalise the bulbs in ground cover, such as ivy, ajuga, or acaena.
Rock garden perennial flowers are mainly used in rockeries, but the smaller ones can also be grown in alpine beds, and the trailing types are suitable for planting in a dry stone wall. The larger kinds can be used at the front of borders, or as edging near pathways and paved areas.
Many kinds of rockery plants are raised from seed sown indoors in April or September. However, the range of seed available is not great, except from specialist societies such the Alpine Garden Society. Most plants are raised by dividing existing plants in October or March, or by taking cuttings of the spreading types between June and September.
Being mountain plants, the majority of them like open, sunny conditions. They are smaller than their lowland cousins because they have adapted to the shortage of soil, moisture and nutrients. Provide them with conditions of very free drainage, and adequate, but not very rich, soil.
The top 10 -15 centimetres of a rockery should be mixed specially, using two parts soil, one part peat and one part sand or grit. Alternatively, coarse sand or fine gravel could be dug into the top layer. Plant in October or March/April. Watch for snails.
Aftercare for rock plants
Keep rock garden plants free of weeds – they just cannot compete. A layer of gravel, grit or chippings helps to prevent weeds, and sets off the plants well. Although rockery plants like free drainage, they are used to regular rainfall and will need to be watered in prolonged dry spells. Many rockery perennials self-seed. This may not be desirable, and can be prevented by trimming off the flower heads after flowering.
Border perennial flowers are used in mixed plantings with shrubs, or on their own in herbaceous borders. Traditionally, the non-woody border perennials were restricted to the herbaceous border, which can be a stunning feature, but demands a lot of attention.
A mixed border of herbaceous perennials and shrubs has several advantages. Its shrub content needs little attention, and provides interest in winter, when the border perennials have died down. The border perennials provide colour and lush foliage in summer to soften the harsher outline of the woody plants. The shrubs provide valuable shelter, and shade in some cases, for the herbaceous perennials that fill in around, between and underneath them. In large gardens, where there is plenty space, island beds of border perennials and shrubs can be planted. Perennial flowers can be used as temporary filler plants until shrubs take up the space. Many border perennials provide good cut flowers.
Border perennials can be raised from seed sown in trays indoors in April, or in seed-beds outdoors in May or June for some kinds. Time and method of sowing varies but the seed-packets give good instructions.
Lift and transplant the seedlings into nursery beds at 30 centimetres apart. Grow them on until they are large enough for planting into their permanent positions, usually on autumn. Raising plants from seed is a cheap way to acquire a stock of border perennials.
Geranium x magnificum
Alternatively, plants can be purchased, or divisions exchanged. Division, by pulling the crowns apart, or by cutting with a spade, is the main method of plant raising. Plants can be divided at any time during the dormant season, but the usual months are October/November and March/April.
Plant border perennials in good, well prepared soil with no perennial weeds. Dig over the site and work in plenty of well-rotted manure, compost, straw or peat. About 100 grams of general fertiliser per square metre should be applied. The site should be sunny for most types, and the soil moist but well-drained. Some types, however, enjoy damp conditions; some like shade, and a choice can be made for hot, dry, conditions too.
Planting time is October/November or March/April, when the soil is moist but not wet. Place the crowns a couple of centimetres deeper than they were before lifting. Plant in uneven-numbered groups for best informal effect.
Aftercare for perennial flowers
Hoe around the plants in spring, to prevent weeds becoming established. Mulches of well-rotted manure or compost help to feed the plants and conserve moisture, but some kinds of mulch can bring weed problems too. Dig out perennial weeds, or paint on Tumbleweed or Roundup when they appear.
As the plants grow, some types need to be staked. Place a few sticks or canes close to the plant and run twine around and through the clump of shoots for support. Put support in place in time to prevent plants flopping around. Some plants will need watering when young, and in a dry summer. Watch for signs of drought, then water heavily.
An attractive combination of blue, pink and yellow
When the flowers fade, the plants begin to die back for winter. By October, most of the nutrients in the flower stalk and foliage will have been re-absorbed by the plant. Leave on the withered flower stems and seed heads – these can be very decorative during winter. As the tops become untidy, they can be cut away and the area tidied up. Every few years, the more vigorous plants will have to be lifted, divided and re-planted to keep them to a reasonable size.
Spring bedding plants can be used in the same ways as summer bedding, namely, in flower beds, in containers, as ‘spots’ of colour between shrubs and border perennials, and even as pot plants, for example, polyanthus and bachelors buttons.
Spring bedding used in hanging baskets is prone to damage by severe winter weather. The baskets should be hung in a sheltered position, or left on the ground in a bright spot until spring.
The seeds are sown in late May or early June in seed trays of good compost, or outdoors in a good seedbed. Water the seed-bed, if necessary, in dry weather. When the seedlings are about 5 centimetres high, lift them, and carefully transplant them to a nursery bed, at a spacing of 20 centimetres each way. Water them if they show any signs of wilting. Protect wallflowers and stocks from cabbage root fly.
In October or November, when summer bedding has been removed, dig over the ground, incorporating some organic material. Rake in some general fertiliser at 70 grams per square metre. Plant spring bedding at a spacing of about 30 – 40 centimetres apart.
Spring bulbs such as tulips and daffodils are planted when the other plants are in place. They are planted from 15 – 30 centimetres apart. Ground for spring bedding must not get waterlogged – the organic material will help drainage.
Aftercare for spring bedding
Remove any weeds that appear. Firm the plants if they are loosened by the wind. After flowering finishes, in late May, spring bedding is usually discarded to make way for summer bedding plants.
Polyanthus and bachelors buttons can be lifted and planted elsewhere until planting time again. Daffodils and tulips can be lifted and lined out in shallow – 10 centimetres deep –trenches until the foliage dies off when they can be lifted and stored in brown paper bags or boxes until autumn.
If only a few brompton stocks or pansies were planted intermittently for ‘spot’ colour, these can be left to give some flower into the summer. Even wallflowers can be treated as a small shrubby plant, left in position for a few years – only trim off the seed-heads.
Very effective use can be made of these colourful plants for filing gaps between shrubs, or between border perennial flowers, particularly in the early years of a garden when a lot of bare ground must be covered quickly and cheaply.
An interesting colour mix with annuals
Some of the summer bedding plants, such as petunia, busy lizzie and bedding begonia, make excellent flowering pot plants for the greenhouse, or the home itself.
The half-hardy annual flowers are raised by sowing seed in pots, or in trays of good seed compost in the second week of March. A few slow developers, such as geraniums, busy lizzies and snapdragons should be sown a few weeks earlier.
Use clean trays and purchased seed compost to avoid damping-off disease of the seedlings. Sow the seed as directed on the seed packet. Cover with a sheet of glass and brown paper. Place the tray in a warm place at 20º Celsius – a warm greenhouse, a heated room, or a special propagator.
Do not place seed trays on top of the television, as this is dangerous. Do not place seed trays in the hot-press – it is too hot. Examine the trays each day and remove the paper when the seedlings emerge. Remove the glass a few days later. At this stage, the temperature can be lower and they will be fine in a frost-protected greenhouse or on a bright window-sill indoors, but be careful they do not suffer sun scorch in the first few days.
Prick out the seedlings, spaced at 5 centimetres by 5 centimetres, in trays of fresh compost, about two weeks after emergence. Harden off the young plants about ten days before planting out by placing them outside by day and taking them in at night.
Dig the ground, working in about 70 grams per square metre of general fertiliser, Vegyflor or Growmore. If the soil is dry, give it a heavy soaking and let it settle for a day. Summer bedding needs good, fertile soil to develop quickly, and flower well. All types enjoy sunshine, but there are a few, such as bedding busy lizzie and bedding begonia, that tolerate light shade.
Using a line to keep the rows straight, plant the summer bedding plants at a spacing of about 30 centimetres each way – a bit more for large types, less for edging and small kinds. If planting time is not dictated by the removal of wallflowers or such like, summer bedding can be planted in early to mid-May in the south and coastal areas, mid to late May in the midlands and north.
Petunias are great value all summer
Do not be in any rush to plant out, because bedding plants can get a severe shock from cold weather, and be disappointing later on. Water the plants immediately after planting, to settle them in.
Aftercare for bedding annuals
If the weather is dry, water the plants to ensure continued strong growth. Watch carefully for slugs and snails, and use slug-killer if necessary. Hoe lightly between the rows as soon as weed seedlings appear. Do not let weeds get beyond the two-leaf stage.
Summer bedding plants are discarded after flowering finishes in October, except for the few perennial types that are retained. Dahlias and tuberous begonias can be lifted and allowed to dry off in a cool shed. Geraniums can be discarded, if cuttings were taken in August. Otherwise, lift and pot up the plants.
Pots and containers
Plant up pots and other containers in early May, if a greenhouse is available. Grow the plants on, and harden them off in the container. In this way the plants will already be well established when the containers are put outside.
Otherwise, plant up containers in mid- to late May and place them on the ground outdoors, close to a sunny wall, until established. Use trailing types for containers, along with some fuchsias, miniature roses, cordylines or small conifers, to give bulk.
Ordinary soil is not good enough for containers. Use half soil, half peat, and add a small fistful of general fertiliser to each bucketful. Keep containers, especially hanging baskets, well watered. For this purpose, line hanging baskets with polythene.