Scaling, chipping, scooping and scoring bulbs
There are several different ways in which bulbous plants can be propagated, other than by division or by seed. These techniques all require more effort and more exacting standards of hygiene and care, however they are very useful for bulbs which do not readily grow from seed or which do not form offsets.
As with other types of propagation, you should only select bulbs which are healthy, typical of that plant and pest and disease free.
Scaling
This method is used on bulbs which are loosely bunched together, so the scales can be removed by hand. Bulbs such as lilies and some fritillaries can be propagated by scaling. It will take between three and four years to produce flowering size bulbs.
Once the top growth has naturally died down from a bulb, lift it, clean it and dry it. Then simply snap off the required number of outer scales, removing them as close to the basal plate as possible. Discard any withered or damaged scales. The parent bulb should be re-planted immediatley. If you wish, you could use all the scales from the parent plant.
Apply fungicide to the bulb to prevent any infections while it is growing, then place it in a plastic bag with a moist mixture of half perlite and half peat/coir or vermiculite. Blow air into the bag (this will provide oxygen to allow the plant material to respire) then seal and label it. Keep the bag in a dark place at around 20°C (a heated propagator or an airing cupboard is ideal).
After a few months you will find that tiny bulbs (‘bulblets’) have formed at the base of the scales. If the scales are softened and not attached to the delicate root structure then they can be carefully pulled off the bulbets and discarded, otherwise leave them in place. Pot the bulblets in a mixture of half loam-based potting compost and half fine grit. Water and label the pots, then cover the tops with a layer of . Grow the bulblets on in a cool, shady place over the summer and in a cold frame over the winter. Pot them on each autumn or spring until they reach flowering size, at which point they can be planted out.
Twin-scaling
Where bulbs are closely packed together this is the alternative method to scaling. Since you are cutting open the bulb you must ensure that your hands, all instruments and the working surface are hygienically clean, wear surgical gloves if you are in doubt.
Remove the roots (though not the basal plate), the tunic and any old, withered scales from the bulb. Cut the ‘nose’ off the bulb (the pointed end) and cut down through the basal plate to divide the bulb into 8 or more segments (the larger the bulb the more segments you can produce). Starting at the outer layer of each segment, peel back the first two scales with your knife, scalpel or fingernail. Then cut downwards into the basal plate to remove these two scales, so that they have a small piece of basal plate attached. Repeat this process until you have as many twin-scales as you require. Treat all the twin scales with fungicide (dipping them in a fungicide solution and drying them will provide the best coverage). Then treat them as described above for scales. The bulblets should form in about 12 weeks.
Chipping
As with twin-scaling, good hygiene is very important for chipping. Prepare the bulb as for twin-scaling and cut down through the basal plate in the same way to provide between 8 and 16 segments or ‘chips’. Treat them with fungicide then manage them in the same way as scales.
The bulbets should show in about 12 weeks, appearing just above the basal plate in between the scales of the parent bulb. Pot up the chips using the same method as for scaling, but without removing any scales. The chips should be planted with the basal plate under the soil and the bulblets covered to a depth of 1cm.This will leave the scales above ground, so they will gradualy rot away as the bulbs develop.
Scooping
This method is often used for hyacinth bulbs and is carried out when they are dormant. Lift, clean and dry the bulb. Then using a sterilised scalpel or a sharpened teaspoon, scoop out the centre of the bulb’s basal plate leaving the outer rim intact. Apply fungicide to the cut surface.
Fill a tray with moist coarse sand to half the depth of the bulbs and stick the bulbs in it with the scooped basal plates facing upwards. Keep them in a warm, dark place (as for scaling) and water the sand occasionally to keep it damp.
After about 12 weeks bulblets should have formed on the scooped out area. Detach them when they are large enough to handle and pot them on as if they were seeds.
Scoring
This follows the same process as scooping but instead of removing all the inside of the basal plate, cuts are made across it or thin wedges of basal plate and the bulb tissues are removed in a cross formation.
