Q&A - Herbaceous

Q. I live in the Midlands/North and want to know if I can leave my Agapanthus in the soil outside over winter. They are strong and healthy producing a wonderful bloom.

A. Your Agapanthus should be fine in the ground over winter providing it does not get too wet, as it really needs well-drained soil. However the roots are best protected by a 15-25cm (6-9") mulch of straw or bracken and if the weather gets particularly cold and the ground frozen (especially cold winds) you should protect the leaves with straw, fleece or bubble wrap.

Q. I have saved seed from the dwarf alstromeria Purple Frost. I remember hearing that alstromeria seed needed special conditions for germination .Can you help with details of these?

A. Altsromeria should not be particularly difficult to germinate if you give them the right conditions. They should be sown in March and placed in a cold frame or greenhouse providing they have a little shade. Prick out the seedlings into 9cm (3") pots and plant out the following spring. It is unlikely however that your new plants will be identical to their parent but you may discover some interesting colours and habits.

Q. Can you tell me how best to grow Eucomis please? Only one of my plants flowered this year. Do they need feeding and if so when?

A. Eucomis need full sun and well-drained soil to flower well. They also should be watered regularly during their growing period and require winter protection when the weather is severe using materials such as bracken, compost and bark.

Q. When is the best time of year to prune\cut away dead leaves on pampas grass. I live in Merseyside and it has finished flowering and there is quite a lot of dead leaves and it looks really ugly at the moment?

A. You can remove the old leaves of your pampas grass anytime in the spring although it is best before the new growth starts. Make sure you wear gloves as the leaves can cause nasty cuts.

Q. When should I remove the old, dead flowers from my cordyline plant?

A. The best way to deal with the flower spike once it has finished flowering is to wait until the flower stalk turns brown and then cut it off about six inches above where it is joined to the plant. Leave the stub for about a month until it dries out and becomes woody. When it reaches this stage, grab the stub firmly and pull it. It should just pull off the plant without doing any harm. This will allow the point where the flower stalk joins the plant to dry out fully. Then, when the stub is removed there is no bleeding of sap which could weaken the plant or cause rotting.