Look after bulbs once flowering is over and you will be rewarded next year

Spring has brought a few surprises with the bulb displays this year, with certain species flowering at more unusual times than expected. Some tulips that should come into flower in unison have flowered weeks apart. For example, the Tulipa ’Strong Gold’ in the Pavilion beds display were around 2-3 weeks later than the other species in the display. All very strange!

A question the garden team often gets asked is ‘How do you keep your bulbs flowering and looking good year after year?’

Bulbs are not like other plants that put down roots to retrieve water and nutrients from the soil to give them the energy to grow. Bulbs are completely self sufficient; except for water, a bulb contains everything it needs in its own little neat package. The whole plant is already pre-formed within the bulb; if you were to cut open a bulb you will find everything from the foliage to the flower tightly packed inside, waiting for the right conditions to grow. Therefore, the bulb has already spent a lot of time and energy in the previous year creating this little package ready to explode into life at the first signs of spring. This is what we need to take into account to ensure they continue flowering and coming back year after year.

Let’s take the classic daffodil (Narcissus pseudonarcissus); once flowering is completed the foliage and dead flower heads can look untidy. The temptation is to cut them down, tidying them up to make room for other seasonal spring/summer plants to take their place. However, this is the time they need to recover and regain their energy. Some people will say to give them a few weeks before cutting them down; some people say tie the foliage into neat little knots which will still allow them to photosynthesise to tidy them up. Yet none of this actually benefits the bulb and it is only ever going to damage or restrict the plants ability to recover and successfully flower in the next spring. The best thing to do is to leave them alone. Once the bulb has gained the energy it needs for next year it will die back and the foliage will turn yellow and straw like. Only then is it safe to cut them back without taking anything away from next year’s bulb and the time this takes will depend on the species. The one thing you can do is dead head the old flowering stems; these can be taken right down to the base. This will stop the bulb trying to put energy into making seed and focus all its energy back into itself for next year. Although, if you have a large patch or drift of bulbs this may not be practical to go round taking all the spent flowers off.

If you grow bulbs in pots, leaving the foliage to die down in its own time can be very frustrating and can look unsightly. It may also prevent you preparing for spring and summer bedding for these containers. A solution for your containers is to grow your bulbs in smaller pots that can be plunged into your main containers. Once flowering has occurred, lift them out and leave them out of the way where they will gain plenty of light and water, whilst still allowing your containers to be planted with something in season to continue on the display into summer.

Jobs for the week

* Weeds are in full growth; hoe regularly to keep on top of them.

* Vent glasshouses on warm days

* Mow lawns regularly

* Divide overgrown perennials

* Prune spring flowering shrubs after flowering

* Start to harden off half-hardy plants but be wary of late frosts.

With thanks to Craig Woodhouse, Horticulturist at RHS Garden Harlow Carr

DIARY DATES

Tuesdays in May, 11am: Harlow Carr Garden Tours Find out more about the garden on a tour with the Friends of Harlow Carr every Tuesday throughout May. A donation of £2 per person is suggested.

Throughout May: The Tulip Trail Tiptoe through the tulips at RHS Garden Harlow Carr as the garden celebrates the colour and scent offered by these beautiful bulbs. Get inspiration for your own garden with a range of striking planting schemes featuring more than 100 varieties of tulip – from traditional beds and borders to quirky containers. Pick up a trail leaflet to guide you to the highlights, and to see Curator Paul Cook’s top 10 tulip recommendations. Don’t forget to visit the Plant Centre to pre-order your bulbs for striking displays next spring. Normal garden admission applies.

Until 30 June: The ‘Language of Flowers’ exhibition The Victorians believed that every flower - and some vegetables - carried a symbolic meaning: a hellebore for scandal, a rose for love. Learn about the symbolic meaning of flowers at an exhibition taking place at Harlow Carr’s library. Normal garden admission applies.