Q. I have a 30′ tree I think it is called a “tulip” tree because its flat green leaf shape resembles a flat open tulip. the tree also has a type of flower that resembles a fluted kings crown. It tapers up in a yellow brown and has a rim od yellow. It is quite beautiful. It has bloomed for the last 20 years or more. This year all the budded flowers are dry shaped ready to open but have not. In fact there is not one bloom that has opened. The tree looks great, no signs of any disease. We have it injected for insect control (read billions of aphids) for probably 10 years. Any help would be appreciated. Bob Miller – Lakewood, WA
A. Yes it sounds like you have the Tulip Tree (Liriodendron tulipifera) which some people see a tulip in the leaf shape and others in the flower itself. Aphids as well as scale (brown round stationary insects along the stem) are both insect pests. But if you are controlling the aphids with the “injected” pesticide you should also control the scale. Horticultural oil sprays are also effective in controlling these pests. Tulip Trees are also susceptible to verticillium wilt (a soil borne fungus) powdery mildew, leafspot and cankers. None of these would directly influence the trees flowering. The condition you describe sounds like bud blast, which prevent the flower buds from opening. Insects, fungal disease or poor growing conditions can cause bud blast. Bud blast occurs on many ornamental plants including true tulips and rhododendrons. Since it takes at least 10 years for the Tulip Tree to flower and you say it has bloomed for 20 you probably have a large tree. Since you know you have aphid problems it is possible that although you are trying to control the aphids systemically it has not been entirely successful. The aphid feeding could be causing the bud blast. The height of the tree makes it hard to verify. You may want to consider hiring a professional that has the proper equipment to assess insect populations and to spray horticultural oil on large trees. If the tree is small enough you can use Ready-to-Spray Horticultural Oil which attaches to your hose end using water pressure.