Names: Scilla, squill, Siberian squill, spring squill, Peruvian squill, wood squill, Italian squill.

Botanical name: Scilla verna, Scilla sibirica, Scilla peruviana, Scilla bifolia.

Of the four species mentioned, three are grown in gardens and one is a wild native flower, namely the spring squill, Scilla verna. This wildflower is quite rare and only found in some coastal areas around the country, notably the eastern coast.

It grows to about 20cm with lilac blue flowers and is often hidden away in loose grass. It flowers in April and May. By comparison, the Siberian squill and the Italian squill, Scilla bifolia, are much more vigorous and competitive. The Peruvian squill is much bigger than the other species with flowers that can be 10cm across.

Family: Scilla is related to the wild bluebell, and the much cultivated garden flower hyacinth. In recent decades, it has been variously named as being part of the lily family, the hyacinth family and latterly the asparagus family, Asparagaceae - although this is the least likely to be a relative, given that its growth habit is quite different.

Garden value

Siberian squill is a very pretty little flower that looks like a smaller version of the native bluebell, which does not flower for several more weeks. The plant is only 10 to 15cm high with a short stem of nodding bells over broad green leaves. It grows best in the open where it gets some sunshine and its pretty blue flowers can be seen to advantage.

The flowers are divided into six petals and these open outwards on a sunny warm day to facilitate pollinating insects that are on the wing in spring. The effect is to have flowers on a warm day and a better show of colour.

Because of its origins in southern Russia, the Siberian quill is not really Siberian but it is hardy and will survive weather much more severe than ever experienced here. It is usually seen growing on a rock garden as a clump of dozens of bulbs, each producing a flower stem. It is also very suitable for a gravel area, where it loves good drainage and lack of competition.

Growing in gritty soil, it produces many seedlings, the seeds falling close to the parent plants. These are just the width of a hollow blade of grass at first and it is easy to damage them without noticing.

The clumps can be lifted and divided to further increase spread. Or seeds can be collected in summer and sown right away.

While this little flower does best in a rock garden, or a gravel area, with no competition from weeds or other plants, it can also cope well in light grass, in the shade of shrubs or tall trees. But not in grass that is tall and vigorous in growth.

Growing squill

Although less well-known, and not as widely available in the shops in autumn, the Italian squill is superb in a lightly wooded setting.

It produces just two leaves with a flower stem, carrying several flowers, between them. The flower stems often flop about, some of the broad starry flowers facing upwards, others downwards. The other scilla occasionally seen in gardens is the first national squill, which, despite the name, is originally from Portugal and Spain. This kind, for a border, has relatively large flowers which can grow to 30cm tall, carrying scores of small starry flowers in purple and violet blue.

It has a distinctive flattened flower spike. Its foliage is easily damaged by frost, and this can greatly reduce flowering.

Plum trees.

Disappointing plum trees

Plum cropping is unpredictable. Some years it can be excellent and, in other years, it doesn’t produce a single fruit. Occasionally, the tree will produce fruit for a few years when it is five or six years old and not produce fruit again. There are several reasons for the poor performance of plums. A heavy crop one year can exhaust the tree and then it flowers very poorly in the following year. Other pressures on the tree can cause poor or no cropping.

Frost

The main reason is frost. Because the plum tree flowers early, frost often kills the flowers, preventing fruit formation. ‘Victoria’ is the main plum variety and it is widely sold. It is reliable in good areas and the best overall. The soil can have a significant effect. Plums like rich soil, especially with lime, but over-rich or heavy soil tends to make the trees very vigorous, not flower so well and not set fruit as easily.

Heavy pruning often puts a plum tree off flowering and fruiting for two or three years until it settles down. It also tends to make the tree prone to disease.

Another very significant factor in some rural localities is the presence of bullfinches. If you have had problems with a plum tree fruiting, apply some sulphate of potash, at 50g per square metre, to favour flowering, toughen the growth of the plant and encourage fruit set.

This week’s reminders

Fruit, vegetables and herbs

Be ready to sow vegetable seeds of most kinds as soon as conditions allow. Onion sets can be put in now. Potatoes can be planted as soon as possible. Feed all fruit trees. New fruit trees and bushes should be planted from pots as soon as possible. Tidy up herb plants.

Flowers

Sow the quicker bedding flowers, such as dahlias and French marigolds, under protection now. If they are delayed much longer, they will be late to come into flower. Gladiolus corms can be planted directly outdoors from now on. So too can lilies, which can also be potted up.

Lawns

Lawns have benefited enormously from a mild winter and spring with plenty of rain. Trim edges of the lawn where it meets borders or paths. Mowing should be regular from now on. Use lawn mosskiller if there’s moss growth. New areas of lawn can be sown.

Trees, shrubs and roses

Finish off any delayed planting of bare-root deciduous tree saplings. Evergreens, both broad-leaved and coniferous, both can be planted as the sap rises over the next two or three weeks. A good watering at planting and two weeks later is usually all they need.

Greenhouse and house plants

Feed and water all greenhouse plants. Sow seeds of tomatoes for greenhouse growing, without delay, also sweet peppers and chilli peppers, or use purchased plants. Sow basil seeds indoors. Re-pot house plants as needed. Clean dust off foliage and begin feeding.

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