My Mexican Heather Is Turning Brown

Growing Mexican Heather

• Mexican heather can grow well in many environments, but it is best to give it well-drained soil and full-to-partial sun. In hotter climates, giving the heather partial shade could help keep the foliage's color from fading. These plants should be watered on a regular basis while they are still growing but less during the winter. Although the heather is fairly resistant to disease and pests, there are three main things that can lead to brown foliage.

Root Rot

• Root rot in general is caused by fungi in the soil. In Mexican heather, the condition is usually caused by Rhizoctonia solani. The disease causes the foliage to thin out and turns the leaves yellow and brown. The fungus can be triggered by excess water in the soil so it is necessary to ensure that the soil is well-drained. Do not plant Mexican heather too deeply as this can cause root rot to form as well.

Flea Beetle

• Flea beetles, with multiple species from the genus Altica, are most active during spring; they attack the undersides of leaves, leaving them brown and damaging the entire plant. Flea beetles prefer to feed on the weed, Oenothera biennis, commonly known as evening primrose. Once this weed dies, the beetles move on to other types of plants in the area. Eliminating weeds in a garden can help reduce the likelihood that flea beetles will attack your Mexican heather. It is also important to use pesticides containing pyrethroids or carbamates during spring and early summer, especially if the beetle is spotted.

Root-Knot Nematode

• The other common pest on Mexican heather, the root-knot nematode, attacks the root system of the plant. The growth of the roots will be stunted and the roots themselves will turn brown. Above the ground, the plant will have poor growth and the leaves may turn yellow and brown. These pests flourish in soil with excess water so it is important to keep the soil well-drained. There are no pesticides to control nematodes once they have infested the plant. If this happens, it is best to cut out the plant and start over with new soil or soil that has been fumigated to kill the nematodes.