Peter Cun­dall: Tips for en­sur­ing rosy re­sults un­til au­tumn

Gar­den­ing guru PETER CUN­DALL says in or­der to en­sure bet­ter colours, longer-last­ing buds and stronger-grow­ing, health­ier and all-round mar­vel­lous blooms on your roses in au­tumn, sum­mer prun­ing is a must.

Sunday Tasmanian - Tassie Living - - TASSLE LIVING - with Peter Cun­dall

Sum­mer prun­ing stim­u­lates the for­ma­tion of new shoots and al­most all pro­duce new, long-last­ing roses in about eight weeks’ time when con­di­tions are cooler

Most hy­brid tea and flori­bunda roses pro­duce about three ma­jor flushes of bloom dur­ing the grow­ing sea­son. The first is from late Novem­ber un­til late De­cem­ber, al­ways on new healthy growth.

There’s an­other bloom­ing dur­ing Jan­uary and early Fe­bru­ary and fi­nal dis­plays of roses oc­cur from mid-April un­til early May, de­pend­ing on va­ri­ety and how and when they are pruned.

How­ever, roses in Jan­uary can be a bit dis­ap­point­ing be­cause tem­per­a­tures are high and sun­light fierce. This causes blooms to rapidly fade, usu­ally be­com­ing fully blown, pale and bleached shortly af­ter open­ing.

There’s no point in al­low­ing highly at­trac­tive roses to be wasted dur­ing hot weather. So when tem­per­a­tures start to get too high I get busy with my se­ca­teurs to pre­vent fur­ther, waste­ful bloom­ing and to force a post­pone­ment un­til cooler con­di­tions pre­vail.

That means cut­ting off all with­er­ing flow­ers and even de­vel­op­ing buds. On av­er­age, each bush rose is re­duced by a third, con­gested branches thinned and any mis­er­able-look­ing, skinny branches cut out al­to­gether.

Sum­mer prun­ing stim­u­lates the for­ma­tion of new shoots and al­most all pro­duce new, long-last­ing roses in about eight weeks’ time when con­di­tions are cooler.

I should add that suck­ers — where root­stocks starts to sprout from be­low graft unions — are al­ways a prob­lem with top-heavy bush roses. If not se­cured to stakes, even slight winds cause them to wob­ble back and forth, tear­ing roots and caus­ing suck­ers to sprout from dam­aged ar­eas.

Cut­ting suck­ers back hard while still ac­tively grow­ing gives far bet­ter con­trol than do­ing the job in win­ter.

Ground cover roses are so tough and re­silient, they can be slashed back al­most to the ground us­ing brush-cut­ters or hedge shears once blooms shrivel. They

can­not sucker be­cause, un­like most other rose plants, they are not grafted. In fact they are among the eas­i­est of all roses to prop­a­gate from cut­tings at vir­tu­ally any time of the year with al­most cer­tain suc­cess.

Old gar­den roses bloom only once so can now be ei­ther dead­headed or old, woody branches cut right out, al­most to the ground.

All prun­ing de­bris must be care­fully col­lected, raked clear and carted off to pre­vent re­in­fec­tion from black spot dis­ease.

A rose gar­den may ap­pear dev­as­tated af­ter a good sum­mer prun­ing but colour­ful an­nu­als can carry through plenty of colour.

If a few large-flow­er­ing glad­i­o­lus corms are shoved into the soil be­tween the roses in early spring they would be com­ing in to bloom in Jan­uary and Fe­bru­ary.

The most im­por­tant job af­ter sum­mer­prun­ing is wa­ter­ing, fol­lowed by feed­ing. Don’t ever make the blun­der of plac­ing sprin­klers among roses. That’s ask­ing for black spot dis­ease to go berserk. This dis­fig­ur­ing, growth-weak­en­ing, par­a­sitic fun­gus is spread by wa­ter splash on the leaves, the main rea­son why roses grown in Syd­ney or the sub­trop­ics where sum­mer rains are com­mon, are of­ten rid­dled with black spot.

Drip ir­ri­ga­tion is per­fect for roses and it’s easy to in­stall one drip­per per plant to avoid get­ting the leaves wet.

An al­ter­na­tive to drip ir­ri­ga­tion is too deeply wa­ter roses early in the morn­ing so wet leaves dry off quickly.

Rose plants thrive if mulched heav­ily us­ing any kind of straw or or­ganic mat­ter. It can even be pushed hard against stems without prob­lems. Chuck a cou­ple of good hand­fuls of blood and bone widely around each plant and wrig­gle it into any mulch. The smell of blood and bone is also a way of de­ter­ring pos­sums and wal­la­bies.

Poul­try ma­nure, ei­ther de­com­posed or as pel­lets is a valu­able source of nour­ish­ment when spread gen­er­ously around roses. Try and get the stuff on be­fore the end of Jan­uary if you can and al­ways wa­ter the ground first and again af­ter the fer­tilis­ers have been ap­plied.

Sum­mer prun­ing en­sures far more roses in au­tumn, bet­ter colours and lon­glast­ing buds and blooms on strong­grow­ing, healthy plants.

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