Botrytis freckles and browns the edges of a Pink Promise rose. (Photos: Debbie Arrington) |
May usually is the rosiest month in Sacramento. Warm, dry days coupled with raging growth hormones make for bountiful blooms and healthy plants.
But not this month. Sacramento area rose lovers report problems usually not seen in mid-spring: Botrytis, powdery mildew and blind shoots. All these issues can ruin rose blooms (or eliminate them all together).
Powdery mildew coats foliage on a Dorothy Perkins rambling rose. |
Common in late fall, botrytis attacks buds as they open, turning them to mush. It starts out looking like freckles, then quickly turns petals brown and soft. Roses quite often refuse to fully open.
Powdery mildew is primarily a foliage fungus, covering leaves and stems with what looks like an explosion of powdered sugar. (It can coat buds, too.) Its activated by temperature; days in the 60s or 70s are its sweet spot.
The good news? When days turn 90s degrees, these fungi disappear. They can’t stand high heat. The forecast for this weekend: 92 degrees.
Infected foliage and blooms will fall off and be replaced by healthy growth. Pick up these discards and dispose of them in trash (not compost). That will help cut down on reinfection.
Instead of a bud, there's only a stub on this Marilyn Monroe rose. |
The solution is easy: Cut the blind shoot off. Prune the stem back to just above the first five-leaf leaflet. The bush will soon sprout a new stem, most likely with a bud at the end.
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Garden Checklist for week of April 21
This week there’s plenty to keep gardeners busy. With no rain in the immediate forecast, remember to irrigate any new transplants.
* Weed, weed, weed! Get them before they flower and go to seed.
* April is the last chance to plant citrus trees such as dwarf orange, lemon and kumquat. These trees also look good in landscaping and provide fresh fruit in winter.
* Smell orange blossoms? Feed citrus trees with a low dose of balanced fertilizer (such as 10-10-10) during bloom to help set fruit. Keep an eye out for ants.
* Apply slow-release fertilizer to the lawn.
* Thoroughly clean debris from the bottom of outdoor ponds or fountains.
* Spring brings a flush of rapid growth, and that means your garden is really hungry. Feed shrubs and trees with a slow-release fertilizer. Or mulch with a 1-inch layer of compost.
* Azaleas and camellias looking a little yellow? If leaves are turning yellow between the veins, give them a boost with chelated iron.
* Trim dead flowers but not leaves from spring-flowering bulbs such as daffodils and tulips. Those leaves gather energy to create next year's flowers. Also, give the bulbs a fertilizer boost after bloom.
* Pinch chrysanthemums back to 12 inches for fall flowers. Cut old stems to the ground.
* Mulch around plants to conserve moisture and control weeds.
* From seed, plant beans, beets, cantaloupes, carrots, corn, cucumbers, melons, radishes and squash.
* Plant onion sets.
* In the flower garden, plant seeds for asters, cosmos, celosia, marigolds, salvia, sunflowers and zinnias.
* Transplant petunias, zinnias, geraniums and other summer bloomers.
* Plant perennials and dahlia tubers for summer bloom.
* Mid to late April is about the last chance to plant summer bulbs, such as gladiolus and tuberous begonias.
* Transplant lettuce seedlings. Choose varieties that mature quickly such as loose leaf.