Common Disease Problems
Botrytis Blight: This causes the older leaves and the center of the plant to rot. It can start with yellowish brown irregular spots on the leaves or water soaked spots on the stems. The fungus turns a fuzzy gray and emits a cloud of spores when touched. Burpee Recommends: Remove infected plants and plant debris to avoid the spread of the disease and make sure plants have good air circulation. Keep organic mulches away from the plants as spores can live in the organic matter. Use pea gravel as mulches they will help decrease humidity around the plants.
Damping Off: This is one of the most common problems when starting plants from seed. The seedling emerges and appears healthy; then it suddenly wilts and dies for no obvious reason. Damping off is caused by a fungus that is active when there is abundant moisture and soils and air temperatures are above 68 degrees F. Typically, this indicates that the soil is too wet or contains high amounts of nitrogen fertilizer. Burpee Recommends: Keep seedlings moist but do not overwater; avoid over-fertilizing your seedlings; thin out seedlings to avoid overcrowding; make sure the plants are getting good air circulation; if you plant in containers, thoroughly wash them in soapy water and rinse in a ten per cent bleach solution after use.
Powdery Mildew: This is a fungus disease that causes a white powdery look on the foliage. This disease weakens plants as it inhibits their ability to make carbohydrates for themselves using sunlight. Burpee Recommends: You can remove infected plant areas, increase air circulation, and try to reduce the humidity in the room. Check with your Cooperative Extension Service for fungicide recommendations.
Root and Crown Rot: A number of diseases can cause root and stem rots. Symptoms include yellowing of the leaves, drying of the leaves and leaf tips, and whole branches may become brown and die. Burpee Recommends: Make sure the soil is very well drained and that the plant does not sit in water. Replace the soil with fresh potting mix for potted plants, after thoroughly cleaning the pot with a 10% bleach solution. Check with your Cooperative Extension Service for fungicide recommendations.
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.
Leaves turn yellow or brown and may drop off: When the lower leaves turn yellow and the growth slows down this can indicate that the plant needs to be fertilized, or that it is rootbound. Burpee Recommends: If the roots are circling around in the pot (rootbound), clip them and repot the plant. For a nutrient deficiency, use Garden-tone as directed on the packaging.
Mealybugs: Flat wingless insects with a white waxy shell that form cottony looking masses on stems, branches and leaves. They suck the juices from leaves and stems and cause weak growth. They also attract ants with the honeydew they excrete, and the honeydew can grow a black sooty mold on it as well. Burpee Recommends: Wash infected plant parts under the faucet and try to rub the bugs off. They may also be controlled by predator insects such as lacewings, ladybugs and parasitic wasps. Check with your Cooperative Extension Service for pesticide recommendations.
Scale: Insects similar to mealybugs, they feature a waxy outer shell and suck the juices from plant stems and leaves. They weaken the plants and make them more susceptible to other pests and diseases and environmental stress. Burpee Recommends: If they are in the crawler stage (moving insects) they may be controlled with a cotton swab dipped in rubbing alcohol, or you may be able to scrape them off with your fingernail. Young plant parts that are infested may be removed. Check with your Cooperative Extension Service for pesticide recommendations such as horticultural oils.
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 Recomends: They may be able to be controlled with a forceful spray every other day. Check with your Cooperative Extension Service for miticide recommendations.
What is the difference between German and Roman chamomiles? They are not related botanically but both have fragrant ferny foliage and white daisy flowers, and both are used in potpourris. German is an annual plant which tends to readily self-sow while Roman is a perennial plant. Roman has a stronger apple fragrance and is a lower growing plant; it makes an excellent groundcover. German grows 2-3 feet tall and works well in flower beds.
Which chamomile is easier to grow? German chamomile is easy to start from seed; ‘Flore Pleno’ chamomile is easier to grow-on from a pre-started plant. Both chamomile-types are easy to grow once established.
Can I grow chamomile in a container? Yes, German and Roman chamomiles are great for containers.
How can I use chamomile as a companion plant? Chamomile can help neighboring plants increase their essential oils and improve flavor and general health of the plants. It is particularly effective planted near members of the cabbage family, onions and mint. You can make a tea from a handful of flowers soaked in cold water for a day or two and use it to help sickly plants of young seedlings.
Which chamomile is used to make tea? Chamomile tea may be made from the flowers or either German or Roman chamomile. Chamomile is caffeine free and is often used as an herbal sleep aid.