Tips and advice from course held in March including propagation
March 7 2011 – Bulbs for colour throughout the year – Part 1.
Early Spring Bulbs
Eranthus – Winter Aconite – Propagation method – Seed in spring. Best bought growing in pots or in the green after flowering. Beware of mice and voles!
Galanthus – Snowdrop – Prop. Method – Division in spring, Seed in summer, Twin scaling in summer, Chipping in early summer. Best bought in pots or in the green after flowering. Wide range of varieties with varying flowering times (and costs !)
Iris reticulata and relatives – Prop. Method – Division in autumn. Plant deep to keep them going from year to year. Another rodent favourite.
Crocus – Prop. Method – Division in late summer, Seed. Rodent food again, definitely their favourite, so very good for baiting mouse traps. Very wide range of varieties. Good for naturalising in grass.
Cyclamen coum – Prop. Method – Seed mid-summer onwards. This and all other varieties of hardy cyclamen grow very well under large deciduous trees and shrubs. Very generous seed producers but mice like them as well.
Leucojum – Prop. Method – Division in early autumn, Seed in late spring. Slower to clump up than snowdrops the snowflakes prefer a reasonably moist soil.
Corydalis solida – Prop. Method – Division in early autumn. Needs to be dry in summer when dormant.
Anemone blanda – Prop. Method – Division mid to late summer. Seed in summer.
Chionodoxa – Prop. Method – Division in early autumn, Seed in autumn. Easy.
Narcissi - Prop. Method – Division in autumn, Seed in autumn, Twin scaling and Chipping in late summer. Vast selection, with varieties flowering in the garden from February to May. Species take time to settle down after planting and are more fussy about needing the right conditions than all the hybrids.
Hyacinth – Prop. Method – Division in late summer, Twin scaling and Chipping in late summer. Can take time to settle into flowering if used in pots for the house and then planted into the garden.
Erythronium – Prop. Method – Division in autumn , Seedin autumn. Resent disturbance and drying out. Divide in
early autumn on a cool damp day and replant with plenty of leaf mould and well-rotted organic matter.
Page 2.
Early Summer Bulbs
Allium – Prop. Method –Seed late summer to autumn or spring, Chipping in summer. Big range of varieties. Some small growing ones can become a problem and are probably best avoided. Many species will self seed.
Lilium – Prop. Method – Division in early spring or autumn, Seed in autumn, Scaling in late summer. Vast range of varieties. Some species can be raised from seed or division. Hybrids are generally increased by scaling. If growing from seed sow fresh and keep moist at all times.
Eremurus – Prop. Method – Division in autumn, Seed in late summer. Do not crowed out with other plants.Sunny position with good drainage.
Zantedeschia – Prop. Method – Division early spring..Most varieties are not hardy. Grow in pots and set out for summer.
Propagation of bulbs.
Health and safety.
Please, wear gloves or remember to wash your hands regularly, to prevent disease spreading to both your plants and yourself when working with any plant material. Take care when handling fungicides and sharp tools. Keep all pots, tools etc scrupulously clean to ensure that you have the best chance of being successful.
Division – Dividing large bulbous offsets – In spring before active growth begins carefully lift a large clump of bulbs. Pull the clump apart. Select the large bulbs with healthy well-developed offsets. Discard any that are withered, mis-shapen or show signs of disease. Pull or cut the offsets carefully from each bulb. Take care to preserve any roots. Dust damaged basal parts with fungicide. Prepare 15cm (6”) pots with a moist, sandy compost. Pot up each offset individually, up to its neck. Label and water.
Dividing smaller bulbous offsets – Lift a clump of mature bulbs. Select the healthy bulbs rejecting those that are dead, mis-shapen or showing signs of disease or pests. Separate any pairs or clumps of bulbs with large offsets into single bulbs by gently pulling them apart without damaging the roots. Clean the bulbs by rubbing with finger and thumb to remove any loose, outer papery layers. Dust bulbs with fungicide. Pot or replant the divided bulbs at twice their own depth and space at least their own width apart in a moist, sandy compost.
Seeds.
Ripening seedheads – Most bulbous seedheads are brown and dry when ripe. Harvest the seeds as soon as the capsules ripen.
Collecting seeds – Cut the ripe seed capsules from the parent plant. Keep in a paper bag or envelope in a dry, airy place for up to 2 weeks. The seed capsules will usually split open releasing the seeds. If not, carefully open the seed capsule and empty out the seed.
Sowing seeds – Prepare a pot or seed tray with free draining seed compost and firm surface flat. Sow seeds evenly over the surface. Scatter a thin layer of fine compost or fine grit over the seeds. There should be just enough to cover the seeds. Label the pot and stand it in a shady area or plunge it in a sand bed to keep the compost from drying out. Plunge beds – Sink pots up to the rims in a bed of coarse sand or grit in a cold frame or under greenhouse staging.
Potting bulbous seedlings .
One year old seedlings are often not sufficiently developed to pot. After the growing season allow the foliage to die back and stop watering. In the second year, when the young bulbs or corms are dormant, repot them in fresh, gritty bulb compost. Place them at twice their own depth and spaced their own width apart. NB After 2 years the seedlings may vary in size as some will have germinated in the first year and others not until the second year. Sort them by size and pot separately.
Scaling and Chipping.
Scaling bulbs .
1) Lift bulbs in late summer or early autumn before root growth starts. Clean the bulb and snap off the required number of outer scales as close to the base of the bulb as possible. Replant the parent bulb immediately.
2) Put some fungicidal powder into a clear plastic bag. Add the scales and shake the bag gently to coat the scales thoroughly with the fungicide powder. Alternatively, soak the scales in a fungicide liquid solution and then drain well.
3) Prepare a mixture of equal parts perlite and peat (or a peat substitute) in a second clear plastic bag. Add the scales. Inflate the bag, seal and label. Keep the bag in a dark place at a temperature of 20C (68F).
4) When bulblets have formed, usually by the spring, take the scales out of the bag. If the scales are soft, gently pull them off but if they are still firm or if roots are emerging from the base leave the scale attached.
5) Pot the bulblets into equal parts of loam-based potting compost and fine grit (5mm size) either individually or several together. Water, label and top-dress with grit. Keep in a cool, shady place over summer. Overwinter in a cold frame or greenhouse.
6) Pot the bulbs into larger pots each spring or autumn. When the new plants reach flowering size, plant them out either in large containers or the garden.
Twin-scaling bulbs .
Select a clean, healthy, dormant bulb. Remove the brown outer scales and cut off any old fibrous roots or dead tissue keeping the base of the bulb intact. Turn the bulb upside down and then cut it vertically in half and then into quarters. Depending on the size of the bulb you can divide it into 8 or more segments providing that each segment retains a piece of the base plate. Peel back pairs of scales from each piece cutting them free of the base with a scalpel or sharp knife. Each pair of scales should have a piece of the base plate of the bulb attached. Dip the twin scales in fungicidal solution and allow to drain. Then treat as scaled bulbs.
Chipping bulbs .
1) Dig up a healthy bulb when dormant and clean off papery outer skin and trim back the roots with a sharp knife without cutting into the basal plate. Cut back to the growing tip.
2) Hold the bulb with the basal plate uppermost. Cut into 8-16 similar sized sections (chips) depending on the size of the bulb. Make sure that each ‘chip’ retains a piece of the basal plate.
3) Soak the chips in a fungicidal solution (make up according to manufacturer’s instructions) for up to 15 minutes to kill any bacteria or fungal spores. Leave ‘chips’ to drain on a rack for about 12 hours.
4) Place ‘chips’ in a clear plastic bag containing 10 parts of vermiculite to 1 part of water. Blow up the bag, seal and label. Keep the bag in a dark place at 20C (68F). Check periodically removing any ‘chips’ that show signs of rot.
5) After about 12 weeks, bulblets should form from just above the basal plate. Pot the ‘chips’ up individually into 8cm (3”) pots in free-draining, loam-based potting compost. Insert each ‘chip’ with its basal plate downwards and the bulblets covered by about 1cm (.5”) of compost. Leave the scales exposed, they will slowly rot away as the bulblet develops. Grow in a sheltered position. These ‘chips’ should flower in 2 – 3 years.