Wool-sower gall

May 4 2017 RHR 107Some of the newly installed oaks on campus appear to have grown cotton balls with pink spots. These are actually a type of tree gall called Wool-sower gall.

This gall is produced by the harmless Cynipid gall wasp (Callirhytis seminator). photo credit: R. Robert

This gall is produced by the harmless Cynipid gall wasp (Callirhytis seminator). photo credit: R. Robert

This gall is produced by the harmless Cynipid gall wasp (Callirhytis seminator). These wasps lay their eggs on a specific plant and the eggs produce the grubs whose secretions cause the gall formation. The gall provides protection and nutrition. Their favorite host plants are oaks.

The galls do not harm the tree, …

Continue reading »

Plants of the Week: May 22

Alcantarea imperialis RMA_003

Alcantarea imperialis ‘Volcano Mist’

What a pleasure it is to be in the presence of such mighty elegance. Tucked seamlessly into the Scott Entrance Garden  is a blooming Alcantarea imperialis ‘Volcano Mist’. These massive beauties can approach 8 feet in diameter and have up to a 3-foot tall flower stalk.

Alcantarea imperialis is part of a large family of tropical plants called Bromeliaceae, of which approximately one-third are endangered in the wild largely due to habitat loss and overharvesting for the retail market. Fortunately, some nurseries have started producing bromeliads from seeds or pups in an effort to save …

Continue reading »

Cedar Quince Rust

April 21 2017 RHR 077This spring, orange goop appears to be taking over the Juniperus virginiana ‘Burkii’ in the BioStream. During damp springs, cedar quince rust (Gymnosporangium clavipes) produces cushion-shaped, orange, gelatinous blisters through the bark where the branches are swollen on cedars and junipers.

During damp springs, cedar quince rust (Gymnosporangium clavipes) produces cushion-shaped, orange, gelatinous blisters through the bark where the branches are swollen on cedars and junipers. photo credit: R. Robert

During damp springs, cedar quince rust (Gymnosporangium clavipes) produces cushion-shaped, orange, gelatinous blisters through the bark where the branches are swollen on cedars and junipers. photo credit: R. Robert

This fungus has a two-host lifecycle.  A few hours of wet, cool (74 to 78 degrees F) spring weather are sufficient for telial swelling on the …

Continue reading »