Penstemons are short - lived perennials that are often grown as an annual . Over 200 species of genus Penstemon exist , each with its own habitat requirements , making them somewhat hard plant to train . Most penstemon species develop good where summers are cool . Penstemons are susceptible to several foliar diseases , so select disease - resistant varieties to assist see to it that your plant are vigorous and less vulnerable to potential leaf disease .
Botrytis Leaf Mold
This fungous disease is spread by wind and water . Initially , brown spots appear on infected leaves . As the diseases advance , bloom appear damaged and ill-shapen . dispatch all septic buds , blossoms and foliage . ruin badly infect industrial plant . Severe infestations may require the software of an organic fungicide .
Rust
This fungal disease have the formation of small white-livered musca volitans on top of foliage . Powdery orange tree to browned spore develop on the undersurface of leaves . wicked plague causes the entire foliage to turn lily-livered and shrivel . Rust is specially active during humid weather . Apply fungicidal soap early in the develop season as a preventive measure . Remove infected leaves and stems as they appear to control the spread of the disease . Destroy ill infect plants .
Powdery Mildew
Leaves overrun with this fungus look disperse with white powder . Powdery mildew primarily round new leaves , causing distorted appearance and lank ontogenesis . spore appear as tiny black dots and are propagate by the wind . dispatch and destroy infected plant before the powdery mildew spore pattern . To help oneself control the disease , unify together one teaspoon bake soda in one quart of H2O and use as a spray . Unlike other fungous diseases , powdery mildew is less of a problem in moist weather , thriving during hot days with accompanying cool Nox .
Foliar Nematodes
roundworm are microscopic , grovelling parasites that aggress and kill the leafage of the host plant . Penstemon plant attacked by nematodes look wilted and wilted . Infected leaves display yellow patches that bit by bit flex bootleg or chocolate-brown . Lesions may finally cut across the entire foliage , causing leaf drop . Plant nematode - resistant cultivars . Interspersing marigold among the Penstemon may drive the parasites .
Prevention of Leaf Diseases
you’re able to take some preventive measures to decrease genus Penstemon ' susceptibility to assault from folio diseases . Purchase disease -resistant cultivars . leave proper spatial arrangement for your flora to give them salutary spark and air circulation . Many foliar disease are spread by hint and rain . Use mulch to help forefend rainwater slop up against the plants . Water the ground around your flowers carefully to help keep leafage dry . Do n’t work in the garden when plants are sozzled . Many fungal spores and bacterial diseases overwinter in taint leaves and flora textile . sportsmanlike up garden debris in the declination . in conclusion , do n’t chuck out of any septic leaves or plant fabric in your place compost heap or bin .
