Archive
July:
Physiological
Leaf Spot of Tuliptree
Hot weather of summer brings with it yellowing and
premature drop of tuliptree leaves. This unexplained disorder, apparently
caused by environmental stress, commonly develops in tuliptrees during
hot, dry weather. An additional symptom that frequently accompanies the
leaf yellowing is the appearance of circular, black spots between the
veins of the yellowing leaves.
Southern
Blight of Hosta 
The cream-colored structures at the base of the rotted Hosta leaf are
fungal "fruiting" bodies known as sclerotia. The basal rot,
ropy or fan-shaped white mycelium, and the presence of sclerotia are diagnostic
for this destructive fungal disease known as Southern Blight (causal organism:
Sclerotium rolfsii). This soil-borne fungal pathogen is an aggressive
stem-rotter of a wide range of species, including not only flowers and
vegetables, but also some field crops and fruit trees. It is favored by
high temperatures and high humidity. Controlling Southern Blight is difficult
because the pathogen has a wide host range and because the sclerotia persist
in the soil.
Tuliptree
Flower
Many trees are slow to mature if grown from seed and can take 10 or more
years to become mature enough to flower. The tuliptree falls into this
category. Also, tuliptrees tend to bloom more on the wood that is most
exposed to sunlight, so in some larger trees, the blooms tend to be high
up in the canopy where they are not as visible. The green outer sepals
often blend in with the foliage when viewed from below.
Photo By: Peggy Sellers
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Garden Flowers 
