Help their heat stress

REGULAR WATERING: HOSE YOUR ROSES DOWN EVERY DAY

It doesn’t matter what time you water, although early morning or late afternoon is best

Beware of red spider and scale that home in on weakened plants.

Like everyone and everything else, the roses are buckling under the heat wave, particularly roses growing in pots. The yellowing of the lower leaves in the centre of the bush is a tell-tale sign, that such roses need more and regular watering.

As most roses stand on paving or are close to a wall, they are exposed to additional heat radiating off these baking hot surfaces.

WATER DAILY

Because rose roots are confined in pots, they cannot go in search of water as garden roses do. With extra heat from nearby hot surfaces, the potting mix dries out quickly and drought-stressed roses become more susceptible to red spider and scale.

If you don’t have the time to water every day, install an automatic or semi-automatic watering system with pipes leading into each pot. If you water by hand, use a hose with a fine nozzle as this will prevent the potting soil from becoming compacted.

It doesn’t matter what time you water, although early morning or late afternoon is best. Water until you see the water running out of the draining holes at the bottom of the pot.

WATER DRAINING AWAY TOO QUICKLY

It seems a common problem with pot roses is that the water rushes through too fast, so the roots can’t absorb it.

Over time the water creates channels in the potting soil so the water bypasses the roots. The solution is to slow down the water as it goes down.

Repeatedly push a stake into the pot all the way to the bottom and wiggle it to make holes in the potting mix. Use a water-absorbent gel or crystals and use the mixture to fill the holes.

Make sure to water immediately until the soil is saturated.

Filling the holes with fresh potting soil is not as effective but may help slow down the water. Then use a thick mulch of pine needles around the rose.

Pine needles work better than any other mulch because they slow down the water, allowing the soil to absorb it.

Wait for about two weeks before adding fertilizer. If the pot is draining too quickly, the fertilizer also drains away without helping the plant.

POTS ON SAUCERS

Another option is to place a saucer under the rose pot to collect the water, which it can re-absorb.

Pots with bottom drainage holes should be slightly lifted so they can draw up the water. When a pot is flat on the saucer, the holes might not allow water to drain or be drawn up by osmosis.

Pots with drainage holes on the side don’t need to be lifted.

Remember roses like water in motion.

TOO MUCH SUN

If possible, temporarily move pots out of the hot midday or afternoon sun into a shadier position. If the pots are too close to a wall, move them away so there is good air movement.

When it is very hot roses won’t mind receiving dappled sun and when the days cool down, they can go back into their original position.

Bear in mind, the ideal position for pot roses is morning sun and afternoon shade.

POT TOO SMALL?

Don’t skimp on the container. The larger the pot the more water it can store, therefore the better the rose will be able to grow and flower.

The minimum size for a pot is 35cm diameter, and the larger variety of rose, the larger the pot.

PESTS THAT LOVE THE HEAT

Pests like red spider and scale home in on drought-stressed plants. That is because the downflowing sap is far more concentrated, which they love.

Both these insects weaken the plant and if the plant loses its leaves the sunburn will kill it.

To prevent red spider, spray with Ludwig’s Insect Spray Plus once a week. Make sure to spray underneath the leaves where the red spider lay their eggs.

Scale tends to colonise the stems. If you see scale, use a soft nail brush or toothbrush and brush off the scale.

Then follow up with Ludwig’s Insect Spray which contains canola oil that will smother any remaining eggs of scale.