Annuals and biennials
Although there are specific definitions for annuals and biennials, in practice there is no clear dividing line.
Hardy annuals are often grown as biennials and some biennials, such as Hollyhocks and Pansies, are left to grow in the border as perennials.
Hardy annuals are often grown as biennials and some biennials, such as Hollyhocks and Pansies, are left to grow in the border as perennials.
All of these plants are, however, invaluable to any garden. They can be raised from seed, so large numbers can be grown very cheaply. They also have many uses, from filling tubs and hanging baskets, filling gaps in borders and rockeries, to being used as feature in their own beds.
Annuals complete their life-cycle in 1 year, whereas biennials are planted one season ready for flowering the following season.
Hardy annuals and biennials are resistant to frost and can be sown in open ground quite early in the season. This means they become established long before the frost prone annuals are ready to be planted out.
Half-hardy annuals (often known as bedding plants) can be severely damaged in freezing temperatures. They need to be sown and kept in frost free conditions, in a greenhouse or cold-frame, in order to germinate and thrive, until the weather has improved enough for them to be planted out.
Hardy biennials should be sown by the middle of the summer. This enables them to become well established in time for the frosts of the winter.
Half-hardy biennials should be kept in a cold frame or greenhouse ready for planting the following season.
Hardy annuals can provide colour from mid-June onwards. They are easy to grow and extremely good value for money. They can be used to fill gaps in borders where other plants have not survived the winter, or where bulbs have finished flowering and died back. They are useful for tubs, the trailing varieties being particularly effective when used in hanging baskets.
Annuals and biennials need as much sunshine as possible, to encourage flowering throughout the summer season. If possible, choose an open position which is visible from all sides.
Annuals complete their life-cycle in 1 year, whereas biennials are planted one season ready for flowering the following season.
Hardy annuals and biennials are resistant to frost and can be sown in open ground quite early in the season. This means they become established long before the frost prone annuals are ready to be planted out.
Half-hardy annuals (often known as bedding plants) can be severely damaged in freezing temperatures. They need to be sown and kept in frost free conditions, in a greenhouse or cold-frame, in order to germinate and thrive, until the weather has improved enough for them to be planted out.
Hardy biennials should be sown by the middle of the summer. This enables them to become well established in time for the frosts of the winter.
Half-hardy biennials should be kept in a cold frame or greenhouse ready for planting the following season.
Hardy annuals can provide colour from mid-June onwards. They are easy to grow and extremely good value for money. They can be used to fill gaps in borders where other plants have not survived the winter, or where bulbs have finished flowering and died back. They are useful for tubs, the trailing varieties being particularly effective when used in hanging baskets.
Annuals and biennials need as much sunshine as possible, to encourage flowering throughout the summer season. If possible, choose an open position which is visible from all sides.
Sowing
The sowing of annuals and biennials depends upon the temperature needed for germination and when they are needed to be in full flower, according to the plans for your garden.
Soil should not be too rich as this encourages the growth of the foliage at the expense of the flowers.
For sowing "in situ" there are 2 main methods, broadcast and in drills. First prepare the area.
Soil should not be too rich as this encourages the growth of the foliage at the expense of the flowers.
For sowing "in situ" there are 2 main methods, broadcast and in drills. First prepare the area.
- Prepare a seed bed by digging the soil over to one spade's depth.
- Rake over the area to remove any stones and create a fine tilth.
- Prepare a plan for the position of each species, ensuring that shade tolerant plants are used in shaded areas.
- Use canes or grit to mark out your plan on the seed bed.
Broadcast
Sowing broadcast is suitable for plants such as Gypsophila and poppies as they produce deep roots and do not like to be disturbed.
Sprinkle seeds evenly in the designated area and then rake lightly at right angles, taking care not to disturb the seeds. Insert a label in the appropriate area for each species used, then water using a watering can with a fine rose.
Sprinkle seeds evenly in the designated area and then rake lightly at right angles, taking care not to disturb the seeds. Insert a label in the appropriate area for each species used, then water using a watering can with a fine rose.
Drills
When sowing in drills the seeds are in straight rows, making it easier to recognize any annual weeds which may appear. Whilst the seedlings are young the bed may appear too formal but, after thinning out, the plants will fill out the spaces as they grow and the appearance will be more natural.
Use a trowel or something similar to mark out shallow drills 8-15 cm (3-6 inches) apart, taking into consideration the final size of the plants. Sow seeds thinly along the drill then gently replace the sol into the drill using a rake or hoe. Label each row for identification and water well using a fine rose watering can.
Use a trowel or something similar to mark out shallow drills 8-15 cm (3-6 inches) apart, taking into consideration the final size of the plants. Sow seeds thinly along the drill then gently replace the sol into the drill using a rake or hoe. Label each row for identification and water well using a fine rose watering can.
Thinning out
Seeds need to be thinned out as they are growing to prevent overcrowding and spindly growth. This should be done in mild weather when the soil is moist. Try to keep the sturdiest seedlings and keep the spaces between plants even. Hold the soil, using thumb and forefinger, around the seedlings you are keeping as you remove the others in order to cause as little disturbance as possible.
Seedlings that have been removed can be used elsewhere in the garden. Only transplant the healthiest seedlings, firming them in and watering thoroughly.
Seedlings that have been removed can be used elsewhere in the garden. Only transplant the healthiest seedlings, firming them in and watering thoroughly.
Buying bedding plants
If you do not have a greenhouse then shop bought annuals and biennials can be used. They are more mature and can be used to fill spaces or even in a bed of their own, especially useful as the colours of the flowers can be specifically chosen to create a particular pattern or match existing plants.
Strong plants with healthy foliage and well developed root systems will give better results. Do not buy plants if the compost is dry or if there is any yellowing or diseased foliage.
Strong plants with healthy foliage and well developed root systems will give better results. Do not buy plants if the compost is dry or if there is any yellowing or diseased foliage.
Aftercare
These plants do not need much maintenance as they have such a short life span but, especially to prolong flowering, certain tasks can be done.
Watering and Feeding: Water regularly using a watering can or sprinkler, soaking the ground. Once established this need only be done in dry weather. Annuals do not need feeding unless the soil is particularly poor. Biennials may benefit but only need to be fed regularly if they are been grown to show in competitions. Remove weeds and self-sown seeds by hand.
Support: Due to the slender stems some annuals and biennials require support. Use pea sticks for plants which are going to grow to 1 m (3 ft) high. Insert the supports when the plants are young so that the growth will hide them as the plant matures. Very tall plants will need to be individually staked. Scrambling annuals which do not have tendrils, or do not naturally twine themselves around supports, need to be tied using soft string.
Dead Heading: The flowering season can be prolonged by removal of flower heads which are dead or faded. This prevents the plant from setting seed, which uses up energy, therefore resulting in an additional flush of flowers. Snap off the flower heads in a clean break. Use scissors or secateurs for thicker stems. Do not dead head plants where the seeds themselves are a feature, as with, for example, honesty (Lunaria). The same applies when the seeds need to be collected for the following season. These can be collected, allowed to dry, and then stored in cool, dry conditions until required.
Watering and Feeding: Water regularly using a watering can or sprinkler, soaking the ground. Once established this need only be done in dry weather. Annuals do not need feeding unless the soil is particularly poor. Biennials may benefit but only need to be fed regularly if they are been grown to show in competitions. Remove weeds and self-sown seeds by hand.
Support: Due to the slender stems some annuals and biennials require support. Use pea sticks for plants which are going to grow to 1 m (3 ft) high. Insert the supports when the plants are young so that the growth will hide them as the plant matures. Very tall plants will need to be individually staked. Scrambling annuals which do not have tendrils, or do not naturally twine themselves around supports, need to be tied using soft string.
Dead Heading: The flowering season can be prolonged by removal of flower heads which are dead or faded. This prevents the plant from setting seed, which uses up energy, therefore resulting in an additional flush of flowers. Snap off the flower heads in a clean break. Use scissors or secateurs for thicker stems. Do not dead head plants where the seeds themselves are a feature, as with, for example, honesty (Lunaria). The same applies when the seeds need to be collected for the following season. These can be collected, allowed to dry, and then stored in cool, dry conditions until required.
