Growing Plants From Bulbs

Aside from the main reason already mentioned above - Spring Colour - there's a number of reasons why bulbs are so popular with gardeners and flower lovers across the globe.

One would be the ease of growing them. Apart from your garden soil being waterlogged, hardly anything can go wrong with bulbous plants. All you need to do is to put them in a hole 2-3 times deeper than the size of the bulb, and replace the soil on top. Job done!

You'll have no worries over watering - no problems with sap-sucking pests like greenfly etc. - all you have to do is enjoy the spring flowering show.

Another reason for their popularity could be that bulbs are quite happy to grow in containers - even the bigger species - and co-exist with other plants such as bedding plants, which will be ready to go in the soil once the bulbs have finished flowering, and return to their dormant state.

This is also what defines "a bulb". Above - I've been using the word bulb to cover the wide range of bulbous plants - which have this thing in common: They develop/produce fleshy, underground organs for storage of moisture and nutrients. The term, then, also covers corms, tubers, rhizomes and tuberous roots.

The true bulb plants are, unsurprisingly, by far the biggest group of bulbous plants. They make up around 50% of this kind of plants, which is more than likely the reason why bulbous plants as a whole is referred to as bulbs.

The onion represents the basic properties of a true bulb. In the very centre of the pear shaped or oval bulb you find the plant embryo itself, surrounded by a number of "fleshy scales".

These scales are held together a the bottom and acts as the storage of moisture and nutrients during the plants dormant period. In most cases (like onions and Hyacinths), the scales are tightly packed round the center, but they can also be loose and swollen, as is the case with the lily.

Most popular bulbs has a paper thin layer of skin round them, which acts as a protection for the scales within, but in some cases, like the lily, this skin is missing, making them sensitive to rough handling.

True bulbs reproduce themselves through off-sets, called bulblets, which can be separated from the mother-bulb and replanted according to the type of plant in question.

Examples of bulbous plants growing from true bulbs are: Muscari, Tulipa, Narcissus, Lilium and Allium.

Corms are another kind of bulbous plants, and at times it can be difficult to tell the difference between the two. They have the same properties as the true bulbs when it comes to a central growing point or two on top, and a baseplate at the bottom with roots on them.

When you cut them open, however, it's a different story. The storage of nutrients and moisture isn't a series of scales inside, but a solid stem base inside.

Another thing that is fundamentally different is that corms are not annuals. During growth and flowering the store is depleted completely, and the corm will start to shrivel and eventually die away.

Meanwhile a new corm, or more, will develop on the top and sides of the old one, and they will be the ones growing and flowering in the season ahead. In some cases, however, small cormlets will form round the sides, and these will only grow to mature plants after 2-3 years.

Examples of bulbous plants growing from corms are: Crocus, Gladiolus, Freesia, Ixia and Acidanthera

Tubers are fleshy, swollen stems that develop and grow underground just like corms, but otherwise they have nothing in common. A tuber has neither the basal plate, nor the protective covering, and there is no neat organisation to the growing points.

A comparison to the tuber from other pats of the botanic world would be the potato. The buds, or eyes as they're often called, are spread over the entire surface of the tuber, and each of them are capable of starting new growth.

Neither do the tubers have a standard size or shape. They're usually knobbly and squat. Most of them will grow bigger as the plant grows bigger, but some of them will diminish in size.

They don't reproduce themselves either, so in order to increase the stock you'll have to dig out the tuber at the end of its growing season, and cut it in two or more pieces, ensuring that each bit has got at least one growing point (eye) on it.

Examples of bulbous plants growing from tubers are: Cyclamen, Gloriosa, Anemone, Eranthis and Begonia.

Like the corm and the tuber, the rhizomes are a bulbous kind of plant that store its nutrients and moisture in thickened/swollen underground roots and stems.

Where the rhizomes stands out from the crowd is in its growing habit. They grow horizontally, and spread outwards, either underground or above the surface.

The main part of the plant is the central growing point at the tip of the rhizome, but as the plant spreads it will form new bud on the top and/or sides of the rhizome, while roots form at the bottom to draw food and moisture from the soil.

Rhizomes are relatively easy to propagate. All you need to do is cutting a branching stem into pieces, ensuring that each piece has got roots and one or more buds.

Examples or bulbous plants growing from rhizomes are: Convallaria, Canna, Achimenes, Zantedeschia and Agapanthus.

The fifth, and final, category of bulbs is known as tuberous roots. Tuberous roots differ from the other four categories by being a cluster of swollen roots, rather than being a swollen stem or a collection of scale leaves.

They areknown by several other names, such as root tuber and tuber-like roots and so on. Dahlia is probably the best known example of a flower that grows from the tuberous root, which otherwise have the same properties as the before mentioned bulbs.

The tuberous roots store away moisture and nutrients to the plant, but while growing, they also create a number of fibrous roots to take up moisture and nutrients from the soil as well.

It is quite common to dig the tuberous roots out of the ground at the end of the season, and let them overwinter somewhere dry and warm, as they're quite sensitive to frost. They can be propagated by dividing the cluster of roots, where every individual storage root with an eye or a bud on it will grow a new plant.

Examples of plants growing from tuberous roots are: Dahlia, Eremurus, Clivia, Alstroemeria and Ranunculus.