Podocarpus, also known as African fern pine or yew pine, is an evergreen conifer that flourishes in U.S. Department of Agriculture plant hardiness zones 5 through 9, however Podocarpus henkelii is hardy to zone 12. The needles form dense spirals and are delicate, lush and pleasantly scented. Podocarpus takes well to pruning and can be grown outdoors or as a large houseplant. While fire blight is not normally a problem for podocarpus plants, correct treatment is critical.
Caused by the bacterium Erwinia amylovora, fire blight infection spreads through heavy rainfall or is vectored to vulnerable plants by insects. The bacteria overwinter in cankers and become active as soon as the weather warms in spring, multiplying and spreading the disease. When the podocarpus is actively growing in spring, then those small to large cankers begin to ooze light tan bacterial material which turns darker when exposed to the air. Fire blight is the most active when the temperature is between 75 and 85 degrees Fahrenheit and rainfall is frequent.
The tips of the leaves on the podocarpus plant’s new shoots can turn black and slowly bend in the shape of a shepherd’s crook. The disease may spread into twigs, limbs and branches. The blackened places remain on the plant rather than falling, giving it a scorched appearance. In case the disease spreads into the primary stem or roots, the podocarpus might perish. Fire blight generally goes from the leaf downward to the origins.
Pruning out infected areas of the podocarpus in summer or winter, when the bacteria aren’t actively propagating, can help slow the spread of the disease. Pruning clippers or shears must be disinfected between cuts and between plants to avoid inadvertently spreading the pathogen to healthy podocarpus plants. The pruning cuts need to add more than only the canker. Cut off the division where the canker is and also the division to which it is attached, leaving only the branch collar of the main division. On the primary stem, you can scrape the illness by removing discolored tissue beneath the bark and also an extra 6 to 8 inches of healthy timber. Copper-based sprays might help slow the spread of the disease but generally can’t control it.
Since lush new growth is especially vulnerable to fire blight infection, heavy nitrogen fertilization and hard pruning to encourage new growth only promote illness. Bordeaux combinations and copper-based sprays implemented since the podocarpus commences actively growing can help reduce the intensity of fire blight infection and supply some protection for plants that are healthy.