Our gardening guru John Stoa answers your questions
Our gardening guru John Stoa answers your queries.
Q. My onions have gone yellow and stunted. What is wrong with them?
The rainy periods of June and July, coupled with cooler weather, particularly up north, gave rise to the spread of white rot. Onions need warm, dry conditions to grow and ripen up. Unfortunately, there are no resistant varieties and the disease remains in the soil for years, so a very long rotation may help but is weather dependent. Some people try to kill the fungus by soaking the affected areas with Jeyes fluid and doing the same two weeks ahead of spring planting.
Q. I was visiting a park in Harlow in Essex when I saw this beautiful mature tree (below). I would love to know what it is.
The photo and leaf specimen look very like a sweet chestnut, Castanea sativa. They grow into magnificent specimens and in autumn produce our eating chestnuts for roasting. In the UK they need a good autumn to ripen up shoots so they will flower the following year, but then they need another good year to produce chestnuts. The chestnut was introduced to the UK by the Romans, who ground the nuts down to make a porridge.
Q. I am looking ahead to next spring and want to buy some tulips for autumn planting. Have you got any favourites?
I use tall tulips for impact in borders and between wallflowers, medium sized for adding into permanent planting and dwarf doubles for tubs and planting between spring bedding plants like polyanthus, myosotis and pansies. My favourite tall tulips are Apeldoorn, Golden Apeldoorn and the white scented Purissima. Medium favourites are Negrita, Red Riding Hood and Cape Town, and my favourite dwarf doubles are Abba, Sun Lover, Monte Orange and Royal Acres.
Q. I have some pink and yellow poppies that just appeared in my garden. They are very attractive, so can I save the seed from these for another year?
Both the Opium poppy and the Californian poppy are very easily spread by wind and birds, and once established can spread widely. They make a great colourful display and are easily controlled.
To propagate from seed, collect the spent seed heads and dry them off ready for sowing the following year. I allow them to spread on to any bare patches of ground for the summer.
Try Delosperma, known as the stone plant or ice plant, as it is in the same family as Livingstone daisies.
These succulent perennials only grow a few inches tall but spread into dense, evergreen, weed-smothering drifts. They thrive in poor, dry, stony soils and are perfect to stick into a dry stone wall. Delosperma nubigenum has yellow flowers in late spring and D. cooperi has purple flowers in summer.