Plants known as "chamomile" include, among others:
Matricaria recutita (syn. M. chamomilla), German or blue chamomile, commonly used in tea.
Anthemis nobilis (syn. Chamaemelum nobile), Roman chamomile, the "lawn" chamomile.
Anthemis cotula, stinking chamomile or dog-fennel, which really DOES stink - used mostly for medicinals.
Matricaria discoidea, wild chamomile or pineapple weed - a sweet mildly pineapple scented and flavored tea herb. It has many of the attributes of German/Roman chamomiles. It is usually the chamomile thought of as "wild chamomile".
Two types of chamomile are commonly planted in herb gardens: German chamomile (Matricaria recutita), a hearty annual that grows to about 2 feet tall and Roman chamomile (Chamaemelum nobile), a low-growing perennial. When growing chamomile for tea, use German Chamomile which produces an abundance of apple scented, daisy-like flowers.
Once you plant chamomile, you have it forever! Which is a blessing - honest. You just need to keep it harvested out of the areas you prefer it weren't in, and establish beds of it in roomy spaces for easy harvesting. The plant can be "weeded" (pulled) out of paths, etc., and the blossoms harvested immediately. Or keep the chamomile "patch" sheared, for bounteous harvests to dry.
Chamomile usually begins to bloom in mid-summer, on into fall. Pinch off the blossoms the day they open. The younger flowers not only have the best flavor, by removing them the plant is encouraged the to bloom more. When you have a good harvest patch, make it part of your morning routine to check for new blooms once a day and harvest them right away. Two cups of fresh blooms will dry down to about ¼ cup, so if you like chamomile tea, be prepared to harvest a LOT!
Immediately after cutting, bring the blossoms indoors and spread them out in a single layer on craft paper or screening. Dry the blossoms indoors, where it is warm and out of direct sunlight.
Be sure the chamomile dry completely - they should crumble easily when rubbed between your fingers. When dry, place them in a lidded glass jar or in a brown paper bag. Don't forget to label!! Chamomile will keep in a dark, cool spot for up to one year.
Pineapple weed, a very short bushy little "christmas tree" about 6" tall is found in waste places such as driveways, along pasture lanes, paths, cracks in sidewalks - in other words, almost everywhere! It is easy to identify when it starts to bloom, by the pencil-eraser sized green flowers. They look like little domed buttons, with no petals.
It can be harvested and dried as for regular chamomile. It makes a delicious light tea, hot or iced. About 2 T. dried flower per 2 cups of hot water.