Amaryllis Red Blotch Disease

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Q: My amaryllis bulbs bloomed nicely, but now the leaves are breaking off. There are red spots on the leaves and on the sides of the bulb. The red spots are even on bulbs that had white flowers, so I would not expect red coloring on the leaves or bulb. What could be causing this?

A: You are accurately describing a fungus disease called red blotch. It used to be listed as Stagonospora curtisii, but it is now listed as Peyronellaea curtisii. This disease can also affect daffodils, snowdrops, crinums, and other bulb plants in the landscape or being grown in pots.

The leaves are often brittle at the location of the red blotch and easily break off at that point. Flowers and flower stalks may become disfigured. If left untreated, the bulbs tend to get weaker and weaker and die after a few years.

For potted plants, prune off the affected leaves, peel off the affected areas on the side of the bulb, replace the potting soil, and treat the bulb with a fungicide. Outdoor bulbs tend to have brown or yellow streaking instead of the red blotches. The tips of the daffodil leaves look like they have been scorched or killed by frost. Prune off the affected leaf tips and treat the remaining bulb, leaves, and soil with a fungicide.

The fungus spreads in wet conditions. Outdoors, wet spring weather is enough for the spread to occur. Indoor bulbs that are stored in damp, humid conditions or bulbs that are planted in soil that stays wet with water in the tray under the bulb are more likely to develop fungal problems. Plant amaryllis with the neck of the bulb up and out of the soil to keep it dry. The fungal spores survive in between the dry, scaley leaves, so peeling some of them off can reduce the number of spores.

Q: We have a hedge of bushes that has not bloomed for the past several years. The hedge needs to be pruned several times during the growing season or else it looks bad. What can we do to force the bushes to bloom?

A: It is often difficult to get hedge plants to bloom because the flower buds are often cut off when pruning the hedge. Spring-blooming shrubs produce their flower buds for the next year’s flowers during the summer. Pruning in the late summer or fall often cuts off flower buds.

Forsythias, lilacs, and most other species of shrubs used for flowering hedges prefer growing in full sun. The more shade they get, the less they flower. As surrounding trees mature, they may cause too much shade. If the shrubs are unhealthy for some reason, such as waterlogged soil or recurring diseases, they may not bloom.

If they bloomed well in the past and have stopped, it may be because old stems do not bloom as well as younger ones do. Most spring-blooming shrubs bloom best on stems two to four years old. Old hedge branches don’t produce flower buds, and the flower buds on young branches are cut off.

Courtesy of Jeff Rugg

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