Amateur Gardening – 10 July 2019

36 AMATEUR GARDENING 6 JULY 2019

Ask John Negus

John has been answering

reader queries for 49 years

Q

My Hydrangea paniculata is in a

large pot with good compost, but

the leaves seem to be dying. There are

no signs of pests or disease, and it looks

like it will soon flower. What is going on?

T Burridge, Wellington, Somerset

A

I suspect that the problem lies in

the growing conditions. Hydrangea

paniculata does best in a spot that is

shaded from the sun for part of the day.

These plants are not fussy about the

pH of their soil, but the soil does need

to be fertile, well fed and slow to dry out.

The best potting compost for shrubby

plants is one with a high proportion of

How can I cheer up a sickly hydrangea?

Horsetail horror

Q

How can I get rid of horsetail?

Jerry Crowton, Lutterworth, Leics

A

The first thing to do is dig out

the horsetail with as much root as

possible, then work in a soil conditioner.

Next, cover the site with weed-blocking

membrane and then anchor it securely.

Finally, make slits in the membrane and

set evergreen carpeting plants to create

a tapestry of colour.

A container-growing

Hydrangea paniculata

will need constant

care if it is to thrive

Horsetail is a deep-rooted

weed and tough to remove

loam, such as John Innes No3. Even the

best multi-purpose composts only have

enough nutrients for four-six weeks of

growth, and once this is exhausted plants

will need supplementary feeding, either

with a liquid or by top-dressing with

controlled-release fertiliser. Feed with

a liquid from early June until the end of

flowering or top-dress in early June.

Loam-based composts hold on to

moisture better than peat-based types,

but all potted plants will need watering

regularly unless it rains a lot every day,

because their roots are constrained

and more shallow, and their compost is

covered by foliage, which blocks the rain.

Wikimedia

All photography TI Media, unless otherwise credited

Q

What is this pretty shrub, please?

Mrs A Crookes, Sutton-in-

Ashfield, Notts

A

This is a form of wintersweet

(Chimonanthus praecox). There

are several forms with crown-like blooms

that range in colour from deep yellow in

‘Grandiflora’ to pale cream in ‘Trenython’.

It is best espalier-trained against a

south-facing wall or fence, where it will

flower better than if it were grown as a

free-standing bush.

A winter wonder

Help for long-term weed solution

Q

Please can you recommend a

long-term solution to weeds?

Ours just keep on coming back!

Andy Woolton, Scunthorpe, Lincs

A

Regular weeding should keep

them under control. However,

using this method alone may mean it

takes a whole season (maybe even

two) to eradicate them.

Roundup is a good weedkiller, but

it needs to be applied in dry weather,

ideally with no rain for 24 hours

afterwards, to maximise its efficiency.

It is a systemic weedkiller that is

absorbed and travels right down to the

plant’s roots, killing it all. However, it

may need more than one application

to be successful, especially with

robust perennial weeds.

If the weeds are proving really

frustrating, try using a brushwood

killer, a heavy-duty pesticide for

woody plants. It should do the trick,

but keep it off your cultivated plants.

A systemic weedkiller should solve

your problems eventually

Wintersweet is a stunning scented shrub

Alamy

Alamy