How To Grow Bulbs / RHS Gardening

What are bulbs?

‘Bulb’ is a general term that covers four types of underground food-storage organ:

• True

  These are fleshy, rounded, underground storage organs, usually sold and planted while dormant. Examples include daffodils, tulips, hyacinths, lilies, onions and garlic. The term is often used to cover other underground storage organs, including corms, tubers and rhizomes.

  bulbs – these are the traditional type of bulb, usually rounded and pointed at the top, with a flat base from which the roots grow. Examples include daffodils, snowdrops and lilies
• Corms – these look similar to bulbs, usually with one or two

  A bud is a small, undeveloped shoot that contains the potential for new growth. Buds are typically found on stems, where they can be apical (found at the tip) or axillary (found between leaf axils) and may develop into leaves, shoots or flowers.

  buds on the top, and the roots grow from the base. Examples include crocuses and gladioli
• Tubers – these are either swollen roots, such as dahlias, or swollen stem bases, such as cyclamen
• Rhizomes – these are swollen stems that grow horizontally, on or just below the soil surface. Examples include bearded irises, lily-of-the-valley and cannas

All of these ‘bulbs’ differ in appearance, but essentially have a similar function – to store food when the plant goes dormant, usually after flowering.

Choosing the right bulbs

Most commonly grown bulbs are simple to grow and suitable for containers and borders, and sometimes for naturalising in lawns. Some can also be grown indoors for flowers at Christmas.

Most bulbs like a sunny spot in free-draining soil, but there are types for all situations, from damp to dry soil, full sun to deep shade.

How and what to buy

They can be bought as

Dormancy refers to a period of inactivity in plants, during which they slow down or stop their growth, conserving energy and resources. This is a natural process that helps them survive harsh conditions, such as winter or drought. Dormancy in seeds is a mechanism that prevents them germinating until environmental conditions are favourable for growth.

dormant bulbs at planting time, or growing in containers, ready to flower. Buying as bulbs is the cheaper option, but ready-planted containers provide instant colour.

They can be bought widely in garden centre and from online suppliers. Dormant bulbs should only be bought around planting time, so they don’t deteriorate in storage. Choose large, firm bulbs with no signs of damage or rot.

A few types of bulbs, such as snowdrops, can also be bought after flowering, when still in leaf (known as ‘in the green’). These specific types establish better when planted in growth, rather than when dormant. They are available from specialist suppliers.

Plants that grow from rhizomes, such as bearded irises, are usually sold in containers, ready for flowering. Tubers, such as dahlias, can be bought when dormant or in containers during the growing season.