Many of my daffodils (some planted in autumn, some old ones) have developed
yellow strips lengthwise along the leaves. What should I do? They are
planted in clay but I dug several bags of sharp sand and manure into the
soil first. The manure was from a garden centre but says that it is mushroom
compost based - could it be that the soil is not too alkaline for them? If
so then what should I feed them with? TIA

--
Hayley
(gardening on well drained, alkaline clay in Somerset)