Magda Smit of Benoni writes My bed of ‘Thank You’ roses have been the best ever this year and I would like them to flower for as long as possible. Can I keep on fertilising them until winter?
Ludwig replies By fertilising them right now with Vigorosa, your roses will bloom into May and June, but after that we move into the coldest time of the year and roses need to go dormant so that they can be pruned in July. For this reason, it is not advisable to fertilise after April, except in warm, subtropical regions such as the KZN coast where it can still be done in May. In very cold areas, fertilising should have stopped in March. Roses need to go dormant so that they can harden off and build up starches and sugars for sprouting in spring, which is when we really want them to perform at their best.