ROSE CARE FOR APRIL
Growing Great Roses - Irrigation and Drainage
by Richard Holtz, Consulting Rosarian
Ideally, roses need 5-6 gallons of water per week. Make sure your roses have good drainage and don’t sit in standing water.
If you plant in terra cotta pots with a single drainage hole make sure that roots don’t find their way through the hole and gradually expand to the point where the hole becomes plugged and the pot cannot drain.
I had ‘Opening Night’ in a big terracotta pot and the root expanded and cut off drainage altogether. I didn’t notice until dormant pruning that the winter rain had filled the pot causing the canes to develop dark blackish spots that resembled a leopards coat. I cleared the blockage and the rose survived, but it took a few years to bounce back and new canes now look healthy.
So, if I use terra cotta now, I elevate the pots by using three bricks laid flat around the perimeter or pieces of scrap redwood. If it is on a patio I use the clay feet, available at nurseries. They are a good solution and more attractive.
I usually irrigate my roses with a 2 ½ foot loop of ¼” drip soaker, with emitters spaced 6” apart built into the tubing. I use this 2 ½ foot loop per rose, which is 5 emitters total. This gives me 2 ½ gallons of water per hour.
I run the zone with roses a total of 2 hours per week which gives me 5 gallons per week to each rose. I secure these loops with U shaped metal stakes to hold them in place. I adjust the run time on my system to take into account the long stretches of fog we often get in coastal Marin. I can up the time during a heat wave, like we often get in September and October.
Typically, you want to water roses to a depth of 16 to 18 inches. This helps send roots down deeper so the plant is anchored better and can survive hot weather better.
MULCHING AND SUN
Mulching is very good for roses. A two to three inch layer is ideal. Mulch should be kept 3-4 inches from the trunk to avoid crown and stem rot problems. Mulch is used to keep weeds down, keep roots cool and slow water evaporation. Compost is a great mulch adding nutrition as it decomposes and improving soil structure.
Roses need a minimum of 6 hours sun per day although some are said to get by with less.
In January 2017 David Austin Roses sent out an e-mail with a few of their roses that tolerate shade better than others. The first rose mentioned was Gertrude Jekyll, a very fragrant pink rose that often places well in shows. I have a customer with a row of 5-6 next to a street with a lot of foot traffic and these roses are admired by many that pass by. Unfortunately, I’ve noticed a few people help themselves to blooms now and then. I think the thorny nature of this rose may defend it from more poaching.
Others mentioned were: The English climber ‘The Pilgrim’, Lady of Shalott, The Generous Gardener (another climber) and the Princess Alexandria of Kent, (a shrub rose I planted last year on the edge of the shade canopy of a Japanese Maple). It probably gets 6 hours of good sun per day in the growing season.
Some other roses which are known to tolerate some shade include:
Floribundas: Playboy, and Iceberg.
Musk roses: Ballerina and Buff Beauty.
Hybrid Musks: Darlow’s Enigma and Sally Holmes.
Hybrid teas: Ingrid Bergman and Double Delight.
Polyanthas: White Cecille Brunner.
When planting roses I suggest placing them two to three feet apart. With the three foot spacing you allow better light penetration and improved air circulation. Both help keep foliar diseases from thriving and allow for easier inspection of the rose for insect infestations.
A YEAR OF ROSE CARE:
July and August
November and December
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Last Modified: 6/23/19