Common Disease Problems
Aster Yellows: Plants are stunted, develop witch's brooms (excessive growth), petals turn green and become deformed. This virus-like condition is spread by leafhoppers. Burpee Recommends: Remove infected plants and control leafhoppers. Remove weeds in the area which serve as alternate hosts to the disease.
Powdery Mildew: This fungus disease occurs on the top of the leaves in humid weather conditions. The leaves appear to have a whitish or greyish surface and may curl. Burpee Recommends: Avoid powdery mildew by providing good air circulation for the plants by good spacing and pruning. Contact your Cooperative Extension Service for fungicide recommendations.
Root Rots: A number of pathogens cause root rots of seedlings as well as mature roots. Burpee Recommends: Practice crop rotation and do not plant related crops in the same area for several years. Pull up and discard infected plants. Make sure your soil has excellent drainage. Contact your Cooperative Extension Service for recommendations.
Rust: A number of fungus diseases that cause rust colored spots on foliage and stalks. Burpee Recommends: Plant resistant varieties. Practice crop rotation. Remove infected plants. Contact your Cooperative Extension Service for recommendations.
Virus (Various causes): The most characteristic sign of virus is tight and dark green mottling of the leaves. Young leaves may be bunched. Young plants may have a yellowish tone and become stunted. Fruit is usually not affected in outward appearance, but it may be smaller and scarcer. Leaflets may point upward and have a grayish cast. Burpee Recommends: Plant resistant varieties. This disease is readily spread by handling. Destroy diseased plants and the plants on either side. Never smoke in the garden as Tobacco Mosaic Virus can be transmitted from a smoker's unwashed hands while handling plants.
Common Pest and Cultural Problems
Aphids: Greenish, red, black or peach colored sucking insects can spread disease as they feed on the undersides of leaves. They leave a sticky residue on foliage that attracts ants. Burpee Recommends: Introduce or attract natural predators into your garden such as lady beetles and wasps who feed on aphids. You can also wash them off with a strong spray, or use an insecticidal soap.
Leafhoppers: Leafhoppers cause injury to leaves and stunt growth. They also spread disease. Burpee Recommends: Remove plant debris. Use insecticidal soaps. Consult your Cooperative Extension Service for other insecticide recommendations.
Slugs: These pests leave large holes in the foliage or eat leaves entirely. They leave a slime trail, feed at night and are mostly a problem in damp weather. Burpee Recommends: Hand pick, at night if possible. You can try attracting the slugs to traps either using cornmeal or beer. For a beer trap, dig a hole in the ground and place a large cup or bowl into the hole; use something that has steep sides so that the slugs can’t crawl back out when they’re finished. Fill the bowl about ¾ of the way full with beer, and let it sit overnight. In the morning, the bowl should be full of drowned slugs that can be dumped out for the birds to eat. For a cornmeal trap, put a tablespoon or two of cornmeal in a jar and put it on its side near the plants. Slugs are attracted to the scent but they cannot digest it and it will kill them. You can also try placing a barrier around your plants of diatomaceous earth or even coffee grounds. They cannot crawl over these.
Spider Mites: These tiny spider-like pests are about the size of a grain of pepper. They may be red, black, brown or yellow. They suck on the plant juices removing chlorophyll and injecting toxins which cause white dots on the foliage. There is often webbing visible on the plant. They cause the foliage to turn yellow and become dry and stippled. They multiply quickly and thrive in dry conditions. Burpee Recommends: Spider mites may be controlled with a forceful spray every other day. Try hot pepper wax or insecticidal soap. Check with your Cooperative Extension Service for miticide recommendations.
Thrips: Thrips are tiny needle-thin insects that are black or straw colored. They suck the juices of plants and attack flower petals, leaves and stems. The plant will have a stippling, discolored flecking or silvering of the leaf surface. Thrips can spread many diseases from plant to plant. Burpee Recommends: Many thrips may be repelled by sheets of aluminum foil spread between rows of plants. Remove weeds from the bed and remove debris from the bed after frost. Check with your Cooperative Extension Service for pest controls.
Helenium Daisy FAQs
Can I grow helenium in containers? The plants grow rather tall and are not recommended for containers.
Does helenium attract pollinators? Absolutely! They are butterfly magnets.
Why is the common name sneezeweed? Will they make me sneeze? No, you should be fine! Native Americans used its dried petals to prevent hayfever.
Is helenium deer resistant? Yes, in fact it is rabbit resistant as well.
When does helenium bloom? The Latin name for helenium is Helenium autumnal, and it has always been a fall bloomer. New varieties have been developed, however that bloom earlier in the season. It will continue to bloom until the first frost in fall.