Spring bulb problems solved

BBC Gardeners' World Magazine

Published: Wednesday, 15 May 2019 at 9:36 am

Bulbs not flowering? Discover possible reasons, and how to improve flowering in future, in our problem-solving guide.

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Bulbs like daffodils, tulips and hyacinths provide glorious colour in spring. However they can be susceptible to rots, mildews, pests and general poor gardening, so it's worth knowing how to identify problems so you can resolve them.

Not sure which spring bulbs to plant? Try a spring bulb pot for bees, or have a go at planting bulbs in lawns, for a more natural look. For something more unusual, check out these parrot and fringed tulips to grow.

Find out about solving problems with spring bulbs, below.

Congested clumps of bulbs

Pale orange-red flowers of Tulipa orphanidea 'Flava'

Pale orange-red flowers of Tulipa orphanidea 'Flava'

Many spring bulbs will stop flowering after a few years. This often happens when clumps of bulbs have grown too big and haven't been divided, as too many bulbs are competing with each other for light and nutrients.

To address the problem, remove faded flowers to prevent the plants from spending energy on going to seed. Dig up, divide and replant large clumps to reduce competition, and add a weekly liquid feed after flowering and until the leaves have died down completely, to increase nutrients to the bulbs, which they will store for flowering the following year.

Bulbs planted too shallowly or too deeply

Planting daffodil bulbs

Bulbs planted at too shallow a depth can develop foliage at the expense of flowers. To avoid this, make sure you plant bulbs at three times their own depth. As a rule it's better to plant too deeply than too shallowly, but avoid overdoing it as the bulb shoot may fail to emerge from the soil, or bulbs may produce foliage but no flowers.

Bulbs planted in the wrong place

Daffodil flowers

Bulbs planted in the wrong place, for example if planted in a shady spot when they require sun, or in a heavy clay soil when they require more drainage, are less likely to thrive than those planted in the correct location. Daffodils will not flower after the first year, if planted in shade.

Mouldy bulbs

A soft mouldy bulb

Mould can quickly develop on stored bulbs. Though they may grow if planted, mould spores can easily spread to, and infect, other bulbs, weakening the stock and reducing the likelihood of them flowering. Before planting bulbs, inspect them for any signs of mould. Throw away any that feel soft or are visibly mouldy. If storing bulbs, do so in a cool, dry place in paper bags or nets. Check them regularly and discard any that show signs of mould.

Planting in waterlogged soil

Magenta, chequered snakes head fritillary flowers

In general, bulbs do best in a well-drained soil and many, tulips in particular, struggle in heavy soils. If you have a heavy soil then plant bulbs that thrive in these conditions, such as snake's head fritillaries, crown imperials and snowdrops. Alternatively, add a thick layer of horticultural grit to the planting hole when planting, to improve drainage. Discover more plants for clay soils.

Tulip fire

Tulip fire symptom on a leaf

Tulip fire is a fungal disease that affects the leaves and flowers of tulips. Fungal spores attack emerging tulip leaves, which typically become malformed, and can result in the rotting of both foliage and flowers. Destroying affected plants immediately, as well as planting bulbs later in autumn, or even early winter, can help reduce the spread of the fungus.

Narcissus bulb fly

Narcissus 'Hawera' daffodil

Narcissus bulb flies lay eggs in the bulbs of Narcissus and others in the Amaryllidaceae family. There are several species but it's the large narcissus bulb fly, Merodon equestris, which causes the greatest problems, as its larvae can destroy bulbs. Symptoms include bulbs producing foliage but not flowers, and, on closer inspection, half-eaten bulbs containing a single cream-white maggot. Deal with the problem quickly by destroying affected bulbs before the larvae leave the bulbs to pupate in the soil.

Forcing spring bulbs

Not got a garden or outdoor space? Lots of spring bulbs can be 'forced' – a process that tricks the bulbs into flowering early, providing winter blooms, perfect for growing indoors. Take a look at nine spring bulbs to force in autumn.

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