With the warmer weather comes more time outdoors. And the more time spent outside leads to observations of things that have gone “uh oh” with plants, whether placed in the garden or potted on the deck.

Here are three pesky threats you may notice on common flowering shrubs and what to do about them.

1) “I began noticing brown leaves on my gardenia and got a late start on inspecting the cause. Many of the brown leaves developed first on branch tips, but there are brown and dying leaves in different spots throughout the plant. And what’s with these white specks and webbing?”

The webbing is a dead giveaway for it being spider mites. First, prune all the dead branch tips off... they won’t come back. Gather as many of the affected leaves that have dropped as possible and dispose of them. Repeated spray applications of neem oil, insecticidal soap or a miticide should all work. Cover leaves thoroughly, including the undersides, and spray either early in the day or in the evening to prevent burn.

2) “Some reddish-brown bug is covering the stems of my roses and there are small, black spots on the leaves.”

The roses are covered with aphids, and the black is what they are secreting after feeding on a plant’s sap. This ‘honeydew’ promotes sooty mold, which is the black on the leaves.

As with the spider mites above, begin treating as soon as there are signs of infestation. Aphids can often be sprayed off with a strong stream of water from the hose. There are natural predators to aphids too. But if nature doesn’t step up, use insecticidal soap or neem oil. Read and follow label directions- repeat applications may be necessary.

3) “Knock Out roses are looking fantastic right now! But small windowpane-like cut outs are appearing in the leaves. I haven’t noticed any bugs.”

Small, green worms are going to be present on the undersides of those leaves. These are rose sawfly or roseslug. When spotted in the earlier, cooler parts of the day, they can be plucked off by hand. Control in April through June is ideal. Horticultural oils and spinosad will also work. Read and follow label directions.

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