/Action plan: Nigel Colborn's essential jobs for your garden this week

Action plan: Nigel Colborn's essential jobs for your garden this week

BEWARE THE COMPETITION

Young trees or shrubs will produce most of this year’s growth over the next three months.

Their need for soil nutrients, root space and, above all, water, will be greater during this time of the year than at any other. 

If grass or fast-growing invasive plants grow close to their trunks, saplings and shrubs will languish.

That is weed good for you why it’s important to keep a ‘roundel’ — a small area of bare ground — around the bases of young, woody plants. 

A standard cherry or young lilac will benefit from being encircled by up to a square metre of soil. More compact shrubs or very young trees will be fine with smaller roundels. 

Nigel Colborn says young trees' need soil nutrients, root space and above all water the most at this time of year

Nigel Colborn says young trees’ need soil nutrients, root space and above all water the most at this time of year

If the bare soil is mulched with leaf-mould, bark chips or even used potting compost, growing conditions will be even better.

Competition from weeds, grass or vigorous herbaceous plants is removed, so the shrub has access to all available soil moisture. 

As they mature, the root systems of trees or shrubs will grow into a widening area. By then, plants close to their trunks will be less troublesome.
Your roundels could become smaller. But it’s still best not to have grass growing right up to the trunks. 

With large, mature trees you can grow non-competitive plants under their branches.

Spring varieties such as primroses, wood anemones, violets or bluebells will flower before the trees come into leaf. 

Free-standing shrub roses or climbers are particularly fussy about root competition, so be sure to keep weeds or grass well away and spread mulches around them. 

KEEP ASPARAGUS WEED-FREE

He says that if you grow asparagus you should tackle weeds now by using a narrow hand-weeder or trowel

He says that if you grow asparagus you should tackle weeds now by using a narrow hand-weeder or trowel

If you grow asparagus, tackle weeds now.

With thistles, docks, dandelions and others with long tap roots, dig deeply using a narrow hand-weeder or trowel. If the soil is in good condition, pulling out annual weeds will be easy. If hoeing, be careful not to slice asparagus spears.

HANGING ON TO PRECIOUS NUTRIENTS 

Remove seed heads or withered flowers from larger types. Keep the bare stems and leaves untouched so they can transfer nutrients into the bulbs

Remove seed heads or withered flowers from larger types.

Keep the bare stems and leaves untouched so they can transfer nutrients into the bulbs

Early bulbs will be over, but if your planting was well-planned, late varieties will look lovely for a few more weeks. Remove seed heads or withered flowers from larger types.

Keep the bare stems and leaves untouched so they can transfer nutrients into the bulbs. Small bulbs wither and vanish quickly after flowering. Tall narcissus and tulips take longer, but are best left until fully withered. If you want to increase bulb numbers or move established ones, lift those now.

That’s riskier than lifting dormant bulbs in autumn, but the bulbs are easier to find. Replant deeply. 

PLANT OF THE WEEK: PURPLE TOOTHWORT, LATHRAEA CLANDESTINA 

Close up, each stemless flower looks like a tiny hooded figure with its hands clasped. It has no leaves, so rather than photosynthesising, its roots latch onto a host plant

Close up, each stemless flower looks like a tiny hooded figure with its hands clasped.

It has no leaves, so rather than photosynthesising, its roots latch onto a host plant

Here’s a freakish thing — a leafless parasite. From a distance, these pretty spring flowers resemble rosy crocuses. But close up, each stemless flower looks like a tiny hooded figure with its hands clasped.

It has no leaves, so rather than photosynthesising, its roots latch onto a host plant — often a willow or alder — to suck up the nutrients needed. Though hard to establish, clumps of purple toothwort can be planted next to young roots of a suitable host.

Harm to the host is negligible. I know of one supplier, avonbulbs.co.uk.

QUESTION

I was given seeds of Gardener’s Delight heritage tomatoes.
When grown, the plants seemed to be of several varieties. Why was this? 

Mr G. Owen via email

Gardener’s Delight are open-pollinated. Professional seedsmen will destroy any which differ from the named variety.

Seed stocks not raised by experts may be less strictly controlled, so the next year’s progeny is less uniform. Seeds of F1 (first filial) hybrids are first crosses with selected parent plants. Their seeds will produce fruits and flowers identical to those of their siblings.

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