Options for Small Flowering Trees

Options for Smaller Flowering Trees

Posted by: Eric Hammond Adams County Extension

Newport Plumb Damaged by Last November's Sudden Hard Frost



As other bloggers have noted, this last winter was hard on woody plants throughout much of the state.  One of hardest hit groups, at least in Adams County, were the traditional smaller ornamental trees, including many ornamental and tart cherries, plums of all types and, to a lesser degree, some varieties of crabapples.   Many of these trees are dead or have severe die back.  



Damage to Crabapple

Some of the species and selections that were affected had been reliable for years and likely still deserve a place in our landscapes.  However, in the interest of promoting diverse plantings I thought I would highlight a few potential replacements which seem to have come through the challenges we have experienced this past winter.



Damage to Crabapple

 

Tatarian maple (Acer tataricum)-



Hot Wings Tatarian Maples

 

This maple is a smaller tree with a spreading to rounded habit which is often somewhat wider than it is tall.  White flowers occur after it leafs out and develop into a double samara fruit by early summer.  This fruit is reddish and persists through the summer providing interest throughout the season.  This fruit is especially showy on selections such as Hot Wings (Acer tataricum 'GarAnn'- a Plant Select introduction).  In the fall the leaves of the tatarian maple turn an eye-catching red-orange. 



Tatarian Maple Flowers

 

Fruit of Hot Wings Tatarian Maple 

 

Russian hawthorn (Crataegus ambigua)-

 

Russian Hawthorn in Bloom

This tree has a rounded habit and attractive gold-yellow bark.  It has white flowers which appear in mid-May in most years and develop into a red fruit.  This fruit persists on the plant into the fall and, at least in our garden, is mostly eaten by birds before it can fall to the ground and become a mess.  The fall color of Russian hawthorn is an attractive yellow with undertones of purple.  Plants will tolerate minimal watering once established.

 

Russian Hawthorn Late Summer

Russian Hawthorn Fruit

 

Japanese Tree Lilac (Syringa reticulata)-

 

Japanese Tree Lilac Early Summer

This plant is small tree with an oval habit and dark green leaves.  It is related to the more common shrub lilacs but has white flowers which occur after its shrubby relations are done blooming (there is one outside our office which actually still is in bloom).  This tree develops a yellow fall color which varies greatly in quality from year to year depending on the conditions during the fall.   

Japanese Tree Lilac Flower

Frozen 2: The tree edition

Posted by: Jane Rozum, Douglas County Horticulture Agent

It’s a bad omen for plants when the weather changes from the relatively mild temperatures we received in October and early November into the flash freeze the Front Range of Colorado experienced the week of November 10, 2014. Plants that weren’t snow-covered and subjected to the bone-chilling winds and below zero temperatures were the worst-hit.

We’ve heard from Tony Koski on the effects of the November ‘Polar Vortex’ on grasses and weeds; Alison O’Connor reported on the plight of roses subjected to the extreme cold. What about those plants that live more than a few feet above ground? What about the trees?

In a typical year, landscape plants can handle the below zero temperatures we routinely receive every winter.  However, the biggest problem with this year's November chill was timing. Plants acclimate well to slowly- declining fall temperatures as we approach winter. When plants experience a rapid drop in temperature following mild weather which doesn't allow for proper hardening,  significant plant tissue damage may result.

We are already seeing the effects of this cold snap on our evergreen trees and shrubs. Austrian, Bosnian, and Norway pines and other non-native evergreen trees are exhibiting brown tip foliage, especially on the south, east and west sides of the tree. The north sides of trees may exhibit less damage because that side of the tree likely acclimated to a greater extent than the sides more exposed to full sun.  Brown, brittle buds, if present, may indicate severe cold injury and death of the growing point.  

Deciduous trees were affected by the cold-snap as well. Some trees never dropped their leaves because the cold-snap interfered with formation of the abscission layer that allows the leaves to fall from the trees. Retention of leaves by deciduous plants in the fall is called "marcescence"; leaves die and wither, but do not fall from the tree. For some tree species like oaks, this is a normal, genetically built-in occurrence. Many of our maples and ornamental pears exhibited marcescence because of the November freeze. This leaf retention won’t hurt the tree, but with the leaves still present, heavy wet snow may cause excessive snow loading and lead to broken branches. The full effect of the November freeze on deciduous trees, however, may not be exhibited until this spring and beyond.

Calllery Pear with  marcescent leaves



What can one do about potential damage caused by this rapid onset cold weather?  CSU Extension recommends winter watering trees every so often when we get relatively warm days (40-50°F) and there isn’t any snow cover. A mulch ring around trees, especially around newly planted trees, is always a good practice. No fertilizers should be provided during the winter season.   At this point, we’ll have to wait and see what happens this spring with our woody plants.