While pollen and allergies are everywhere, there are some plants that can cause more allergies than others. Watch local forecasts and check on what pollen is most in effect in your area, and test yourself for allergies if you are constantly bothered by hay fever-like symptoms. Whether it's a skin allergy or nasal allergy, these plants should be on the watch list if you are susceptible to itching and sneezing.
Taraxacum officinale, the dandelion or blowballs, is from the aster/daisy family. It is an easy growing and fast growing perennial. It is typically referred to as a lawn weed. Flowers are yellow and 2 inches wide appearing 2 to 18 inches tall. Leaves are basal and 2 to 15 inches long. These grow best in full sun or partial shade. Propagation is via seed. Besides a lawn weed, these are grown for salad greens.
Helianthus annuus, the common sunflower or mirasol, is from the aster/daisy family. It is a fast and easy growing annual that attracts butterflies and birds to the garden. While there is vast differences depending on cultivar, most have yellow ray flowers 8 to 12 inches wide holding a brown seedhead center. They are roughly 8 to 15 feet tall with hairy leaves. Plant in full sun in well-drained neutral to alkaline soils. Propagate via seeds. The seeds are edible and attract birds and wildlife. Some may get contact dermatitis from the plant.
Ricinus communis, the castor bean or castor oil plant, is from the spurge family. It is a fast-growing, evergreen annual shrub. It will get up to 40 feet tall and 15 feet wide with a woody trunk. Leaves are reddish green or purplish, glossy and 12 to 30 inches wide. Flowers are greenish yellow and are 8 to 18 inch tall spikes. This is highly poisonous in its seeds and its foliage. It grows in any soil in full sun. They can self sow or propagate via seed. It is typically planted for a tropical look.
Liquidambar styraciflua, the sweetgum or redgum, is from the witch-hazel family. It is a fast growing tree with good fall foliage. This tree can reach over 100 feet tall with leaves 4 to 7 inches wide and barely seen flowers. Spiny spheres are seen after leaves drop. Plant a sweetgum tree in full sun to filtered shade in a moist well-drained area. Propagate via seeds.