Most trees with petaled flowers, like crabapple and redbud, finish blooming in May. We have three trees in bloom now that do have petals. These are catalpa, linden and Japanese tree lilac.

  First I’ll explain what I mean by petaled flowers. Not all flowers have petals. They have other flower parts, but no petals. Trees whose flowers have no petals are wind pollinated and do not need to attract pollinators.

   Lucky for us, some trees have colorful petals to help attract pollinators.  While most are fruit trees or small ornamental trees, those blooming now are good size shade trees. And we need large trees in our communities.

  If you’ve noticed a tall tree with large, heart-shaped leaves loaded with large white blossoms, these are Catalpa.  It is not native to Nebraska but was brought here to be planted, then harvested for fence posts.

   If you have a chance, look closely at white catalpa flowers. They are tubular shaped with beautiful red markings. These markings are nectar guides that help guide insects to the flowers sweet nectar to ensure pollination.

  Plants cannot move and have developed ways to attract pollinators to their blossoms. Without pollination, sexual reproduction through seeds would not occur.

   If you need a large tree, consider catalpa. They are not overplanted and have very few disease and insect pests. During high stress years, they can be infected with verticillium wilt disease; but this is fairly rare.

   Pollinated catalpa flowers produce one to two foot long capsules full of seeds. They are easy to clean up and should not deter anyone from planting this tree. The flowers, large leaves, and long fruits give the tree an interesting tropical appearance.

   If you are walking or biking and notice a sweet, pleasant aroma, look around. You are likely near a flowering Linden. The prolific cream colored blossoms are much smaller than catalpa and very aromatic.

   The scent attracts bees and a common name of linden is bee tree. Another common name is basswood. Don’t worry about planting this tree. When bees are busy gathering nectar for honey or pollen to make bee bread for their larval bees, they rarely attack.

   Hive bees tend to attack only if their hive is threatened. Many bees are solitary and do not live in a hive. Rarely, if ever, do they sting. If you step on one or grab one in your hand, it might sting.

   While Lindens are becoming overplanted, they have few pest issues and because of their importance for pollinators, they are still a recommended shade tree. Consider an American linden over a little-leaf linden.

   Trees with fluffy bunches of white blooms on the ends of their branches are Japanese tree lilac. They are a tree form of lilac but bloom in June with large white flower clusters.

   This is a smaller tree, but can grow to 30 feet to provide shade. Japanese tree lilac is not overplanted and would be a good tree to plant in place of the much overplanted ornamental pear we are losing to fire blight disease and other environmental issues.

   When selecting trees and shrubs, do not overlook those whose flowers have petals.  While pollinators feed on the pollen or nectar of trees with petalless flowers, those with petals are more ornamental and likely to attract even more pollinators. 

   Additional trees for pollinators include serviceberry, Ohio buckeye, black cherry, hawthorns and prickly ash. This is not a true ash and will not be attacked by emerald ash borer, but watch out for the thorns.

By: Kelly Feehan, Extension Educator - Release: June 15, 2017