Home & Garden: Flowers before leaves | PostIndependent.com

Home & Garden: Flowers before leaves

Curt Swift
Free Press Gardening Columnist
Mulberry male catkin
Curt Swift |

Quite a number of species of trees produce flowers before leaves. Most of us are familiar with the Redbud, and the beautiful red or pink blossoms covering their branches in early spring. As these flowers fade, leaves take their place. The ornamental pear trees around town were white with flowers earlier this spring, but those flowers are now gone and have been replaced by leaves.

Mulberry trees also bloom early, but lack the colorful petals of redbud and pear trees. The mulberry’s flowers are borne in tight cylindrical clusters that hang down from the bud. On female mulberry trees this catkin turns into a fruit resembling a blackberry. The immature fruit are at first white or light green and slowly turn pink, red, and finally black as they mature.

Many people consider the female mulberry to be a major nuisance because the ripe fruit stains whatever it drops on. When tracked into the home it stains carpeting and even wood floors. The birds don’t help as their purple-infused droppings tend to make things even worse. Mulberry fruit should not, however, be ignored as it makes great pies and jam and when boiled down into a syrup is very flavorful.

The fruitless form of mulberry is what most people select when choosing one for their yards. This is a male tree. It still produces catkins as is shown in the photograph, which drop from the tree as the leaves expand, but they are in no way as messy as the fruit from the female tree.

The Siberian elm is another tree which develops its crop of seeds before putting out its leaves. When these seeds drop, they plug up gutters and storm drains before being washed into the river. The cotton-less Cottonwood also is a male.

The mulberry, cottonwood, and elm are wind pollinated; the redbud and pear are pollinated by insects. Insects use colorful petals to guide them to the nectar and in the process they pollinate the flowers. You can consider these colorful displays as landing strips for pollinators. Trees like mulberry, cottonwood, and elm are wind pollinated and have no need to put on a colorful display to entice insects to their flowers. As a result the flowers of these trees are quite inconspicuous.

Trees tend to produce more flowers when they have been stressed during the previous year. When trees put out a large crop of flowers, like our Siberian Elms did this year, they use up a great deal of energy which results in less foliage and shoot development resulting in a sparse appearance. A shot of fertilizer can increase their vigor and encourage them to store more carbohydrates for the remainder of the season, resulting in a healthier tree the following spring. Some trees, such as the Catalpa in front of my home, are just starting to leaf out while other trees, which should be fully covered with leaves, aren’t.

A number of silver maple trees around the valley have leaves on their bottom branches, but their tops appear dead. This could be due to a fungus known as Verticillium wilt, which plugs the vascular system (i.e. the water and nutrient conducting vessels), but is most likely the result of this past winter. If these trees do not leaf out by the end of this month, training the tree to restructure a new top or completely removing the tree and replacing it are options you should consider. If you do nothing about the dead wood in these trees, they will be ideal for invasion by insects and disease organisms and become a source of pests to spread to other silver Maples in the area.

When you have what appears to be dead branches in your tree, it is best to have a wait and see attitude. Give the tree a chance to recover. Don’t jump to the conclusion the dead-appearing branches need to be removed. I’ve seen many homeowners remove healthy branches believing they were dead.

If you are not sure about your tree you can always contact a consultant or arborist to confirm your diagnosis and take corrective measures. I have also seen property owners make improper pruning cuts, which resulted in damage to a major branch or trunk or remove an excessive amount of living tissue in the pruning process. The latter reduces the amount of sugar and starch available to the roots resulting in root death. The tree might produce “feather growth” on the lower part of the trunk to increase sugar and starch production to the roots. Feather growth is best left on the trunk for a couple of years to strengthen and invigorate the root system.

GJ Free Press columnist Dr. Curtis E. Swift is a retired horticulture agent with the Colorado State University Extension. Reach him at Curtis.Swift@alumni.colostate.edu, 970-778-7866 or check out his blog at http://SwiftsGardeningBlog.blogspot.com. He owns Swift Horticultural Consulting and High Altitude Lavender.

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