Gardening tips for April - Roses

Rosa Banksiae lutea Photo: Peter Beale's Roses

Rosa Banksiae lutea Photo: Peter Beale's Roses - Credit: Archant

April is one of the most exciting months for roses for it is now that the very first displays of the season begin

The ravishing Rosa Banksiae ‘Lutea’ is one of the earliest roses to burst into flower on warm protected walls, closely followed by the shrub Rosa ‘Canary Bird’, on whose long arching stems a mass of musk scented yellow flowers appear. How perfect it is that these spring flowering roses are yellow – the colour that is all around us at Eastertide.

February/March was a busy time amongst the roses even whilst the rest of the garden – the herbaceous borders and shrubberies – stood mute, still and cold. I always find it amazing how nature prescribes a natural order of activity in the garden, for whilst those same borders now clamour for attention, roses can, to a degree, be left to get on with the unfurling of their leaves – but not entirely!

As April progresses, the roses are edging towards bud burst and this is the moment to give them a second feed. The first, in February, will have been high in potash. This one, in early April, should be more balanced with some nitrates (not too much or you get all leaf and floppy growth) and more or less equal amounts of phosphate and potash and with a range of trace elements. I scatter round the roots a granular rose feed where the correct balance is all prepared so this makes life easy. What is important, however, is not to chuck on an extra handful for good measure, nor to feed too frequently in the hope of achieving even better results, nor to use the fertiliser you were putting on the vegetable patch just because you happened to have it in your barrow. To do so would be like feeding your roses junk food – roses are certainly greedy and can easily suffer from malnutrition (when blackspot and thin leaf cover will be the surest sign) but they need food at regular intervals (probably three times a year) and like us, the food needs to be suitable – so read the packet and follow the instructions to the letter. There is much to be said for changing the food from time to time to find out what works best on your soil and to prevent resistances being built up.

Spraying against pests and diseases is not everyone’s inclination: but if one were to spray only once in the year, this would be the most important time, just as the leaves start to unfurl, catching the first signs of infestation before they take hold. Roses like a slightly acid soil; a regular spray of Sulphur Rose, spraying both sides of the leaves (and thereafter monthly if you can possibly find the time) will lower the pH in the soil and deter black spot. (You may have used Sulphur Soil earlier in the season – now is the time for Sulphur Rose.) Rose Clear Ultra is another spray, this one systemic, that will deal with greenfly, blackfly and other aphids as well as Blackspot. It too contains a (smaller) amount of sulphur: I find a slight disadvantage of sprays containing sulphur is that they leave a white, watery residue on the leaves until the next downpour so I try not to do it just before visitors appear! Nonetheless both are very effective. Uncle Tom’s Rose Clear is another excellent systemic drench that can be used as a foliar spray which encourages healthier growth and increases disease resistance. If spraying is not your thing, try a watering can of Epsom Salts around your roses two to three times during the growing season and start now. I would use one tablespoon of salts to a gallon of water and see how that goes (or you can sprinkle it round the base of the roses and water it in). A word of caution generally against spraying: do not spray rugosa roses at all – they do not need it and the spray may scorch their foliage.

Pruning now is hardly a task at all – take out any crossing branches that you may have missed earlier in the year, any suckers appearing from beneath the graft and of course any bits that are dead. Remember that roses, particularly shrub roses, are better not pruned at all until they have produced mature wood so leave well alone for their first few years. Floribundas may need attention now for they are pruned a little later than others. They are more vigorous than shrub roses and need quite hard pruning. Flowers are produced in clusters at the end of shoots and on new wood so in early April shorten stems to a foot or so from the ground aiming for 2–3 inches above last year’s cut. When you have three or four ‘steps’ in these stems from cutting them thus each year, cut back into older wood to start again. As always, cut to an outward facing bud and angle the cut down from the bud. The tying in of new growth on climbers and ramblers is easily done now when the shoots are so flexible.

Having done what you can to nip in the bud the nascent blackspot and aphid and having checked over the roses for last minute pruning needs, make sure the soil beneath is as clear of fallen leaves as you can possibly make it – it is a tiresome task but one that really helps: with the spraying and cutting and tying in, debris will have fallen. Another mulch now and you will have done all you can. If you have manure make sure it is well rotted or it will burn the plants – it should be at least three to four years old and workable: if it lies around the plant in great lumps, any self-respecting worm will go somewhere else. If necessary incorporate some leaf mould or compost into it so that it spreads well over weed free, debris free and well-watered soil. Lucky Roses.

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