Questions, answers and jobs for the coming week

Delphinium Excalibur White

Delphinium Excalibur White

Gardening: 5 of the best greenhouses

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Brian answers readers’ horticulturalquestions

I have grown a delphinium called Excalibur White (pictured) in a 12in-square pot. It has produced seed heads. How can I save the seeds and can the plant be divided? ED, North End.

The seeds can be saved, when the pods go brown. Put a brown paper bag over the top of one of the bunches of seeds. Tie the base of the bag so the seeds are not lost. In a fortnight, shake the bag and you’ll hear seeds. Keep them dry in a labelled envelope and sow in seed compost next April. The original plant can be divided in late November once it has all died down. You must renew the container’s compost.

We have three pots of euphorbia Bonfire. Two are OK, but the leaves on the other have shrivelled. BJD, Alverstoke.

Most euphorbia grown for autumn colour die down during the autumn but come again in the spring. Take it out of the pot, shake off the compost and if the roots are plump it will grow next year. Change the compost in all three pots. Use John Innes No3, but add 10 per cent extra sand and mix really well.

We visited a garden and saw a plant by a stream. It had beautiful foliage, was about three feet high with lots of red and pink flowers. The flowers look like hundreds of dots which open into tiny petals. The flower groups were like pyramids. What were they? G and PJ, Denmead.

They are astilbe and you’ll find them at your garden centre, often in the aquatic section. The best time to buy them is during early June. We grow them as they are very successful in wet ground.

JOBS FOR THE WEEK

This is an excellent time to book the mower in for a service. If done now it will be finished in three weeks. If left until spring, everyone else has beaten you to it and that grass keeps growing while you wait.

Thin out autumn-sown carrots. Earth up the soil over the bases to prevent the tops going green. Keep the crop covered with insect barrier mesh as carrot root fly is around again.

Sow autumn-sown varieties of broad beans. It is essential the right ones are sown. Aqua Dulce are suitable. Sow single seeds in insert cells for best results. Plant out when seedlings are two inches tall.

Take off old rhubarb leaves. Use these between a layer of mowings. This helps the composting process at this time of year.

How’s the winter digging going?

Shall we leave the fallen leaves on the lawn or pick them up? If you love the lawn you will pick them up regularly. Use a mower with a collection box.

If you usually put leaves in a wire mesh cage, line the inside with old compost bags making sure the black colour of the bags is facing the garden – it looks smarter. This lining of polythene keeps the leaves moist and hastens decomposition.

Buy some tulips. These are best planted in late November when there are fewer slugs. Get hold of some sharp sand to put into the planting holes. This reduces slug damage.

Make sure anything which is going on to the bonfire is kept dry to reduce the amount of smoke. PLEASE check there are no hedgehogs underneath the bonfire.

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