Possum Haw Viburnum, Shrub of The Day

Viburnum nudum 'Winterthur'
    Possum Haw,  Swamp Haw,  Possum Haw Viburnum

Type    Shrub, woody plant
Hardy range    5A to 9A
Height    4' to 6' / 1.20m to 1.80m
Spread    4' to 6' / 1.20m to 1.80m
Growth rate    Average
Form    Rounded
Exposure    Partial shade or partial sun to full sun
Persistence    Deciduous

Bloom Color    White
Bloom Time    Spring

The flowers are fragrant and showy.

Environment
This plant tolerates drought, occasional wetness and some salt.
This plant will grow in very dry to occasionally wet soil.
Suitable soil is well-drained/loamy, sandy or clay.
The pH preference is an acidic to slightly alkaline (less than 6.8 to 7.7) soil.

Leaf Color    Green
Fall Color    Purple and red
This plant has attractive foliage and attractive fall colors.

Culture Notes
Viburnum nudum 'Winterthur' has received the Gold Medal Award from the Pennsylvania Horticultural Society.  It likes moist, acid soil and will do very well in a wet site. Fall color is best when planted in full sun.  Another viburnum nudum is needed for cross-pollination if the attractive fruits are to develop.   They appear in clusters and will change from pink to dark blue. Plants appear more open than other viburnum shrubs. Some stems can be cut near to the ground every year to keep the plant small.  Foliage is shiny bright green. This plant is considered mostly allergy free and causes little or no allergy problems in most people.

Planting and establishing shrubs

The most common cause of young plant failure is planting too deep.  Plant the root ball no deeper than it was in the nursery.  In most instances, the root flare zone (point where the top-most root in the root ball originates from the trunk) should be located just above the landscape soil surface. Sometimes plants come from the nursery with soil over the root flare. If there is soil over this area, scrape it off.  The planting hole should be at least twice the width of the root ball, preferably wider.  In all but exceptional circumstances where the soil is very poor, there is no need to incorporate anything into the backfill soil except the loosened soil that came out of the planting hole.  Never place ANY soil over the root ball. If a row or grouping of plants is to be installed, excavating or loosening the soil in the entire bed and incorporating organic matter enhances root growth and establishment rate.

Weed suppression during establishment is essential.  Apply a 3-inch thick layer of mulch around the plant to help control weed growth.  Keep it at least 10 inches from the trunk.  If you apply it over the root ball, apply only a one or two inch layer.   This allows rainwater and air to easily enter the root ball and keeps the trunk dry.  Placing mulch against the trunk or applying too thick a layer above the root ball can kill the plant by oxygen starvation, death of bark, stem and root diseases, prevention of hardening off for winter, vole and other rodent damage to the trunk, keeping soil too wet, or repelling water.  Regular irrigation through the first growing season after planting encourages rapid root growth, which is essential for quick plant establishment.

Possum Haw Holly, woody plant of The Day

Ilex decidua 'Sundance'
    Possum Haw Holly,  Deciduous Holly,  Winterberry

Type    Tree, woody plant
Hardy range    6B to 9A
Height    15' to 25' / 4.60m to 7.60m
Spread    10' to 15' / 3.00m to 4.60m
Growth rate    Slow
Form    Oval and rounded
Exposure    Full shade to full sun
Persistence    Deciduous

Bloom Color    White
Bloom Time    Spring

Environment
This plant tolerates drought and flooding.
This plant will grow in very dry to wet or submerged soil.
Suitable soil is well-drained/loamy, sandy or clay.
The pH preference is an acidic to slightly alkaline (less than 6.8 to 7.7) soil.

Leaf Color    Green
Fall Color    No change in fall color

Culture Notes
Lower branches are often removed to form a small tree with a tight head of foliage along the outer portion of the crown.  Interior leaves are often shaded out and drop from the tree.  If lower branches are not removed, the plant develops into a large, spreading mound of foliage reaching to the ground. This plant is considered mostly allergy free and causes little or no allergy problems in most people.

Often found along stream banks in the wild, Possumhaw tolerates wet soil and can be used to stabilize stream banks.  It can also be utilized as a large accent shrub or small tree planted in a lawn area as a specimen or near a patio.  Allow for plenty of room for this plant to spread since they look their best when they develop a symmetrical canopy.  They would make a good plant near water retention ponds and other areas which regularly accumulate water.  They are also suited for planting into raised planters or containers.

Maintain adequate mulch area

Clear all turf away from beneath the branches and mulch to the drip line, especially on young trees, to reduce competition with turf and weeds. This will allow roots to become well established and keep plants healthier. Prune the tree so trunks and branches will not rub each other.  Remove some secondary branches on main branches with included bark.  This reduces the likelihood of the main branch splitting from the tree later when it has grown to become an important part of the landscape.  Locate the tree properly, taking into account the ultimate size, since the tree looks best if it is not pruned to control size. The tree can enhance any landscape with its delightful spring flush of foliage. It can be the centerpiece of your landscape if properly located.

Tree establishment specifications

Choose good quality trees for planting. The most common cause of young tree failure is planting too deep.  In most instances, the point where the top-most root in the root ball originates from the trunk (referred to as the root flare zone or root collar) should be located just above the soil surface.  You may have to dig into the root ball to find the root flare. If there is nursery soil over this area, scrape it off. Never place ANY soil over the root ball. The planting hole should be at least twice the width of the root ball, preferably wider because roots grow best in loose soil.  In all but exceptional circumstances where the soil is very poor, extensive research clearly shows that there is no need to incorporate any amendments into the backfill soil. Simply use the loosened soil that came out of the planting hole. Simply planting with the topmost portion of the root ball slightly higher than the surrounding soil might still install the tree too deep - be sure to locate the root flare.

Weed suppression during establishment is essential.  Apply a 3-inch thick layer of mulch to at least a six-foot diameter circle around the tree. This area should be at least two feet in diameter for each inch of tree trunk diameter and maintained during the establishment period.  Apply a thinner layer of mulch directly over the root ball but keep it at least 10 inches from the trunk. This allows rainwater, irrigation and air to easily enter the root ball and keeps the trunk dry.  Placing mulch against the trunk and applying too thick a layer above the root ball can kill the plant by oxygen starvation, death of bark, stem and root diseases, prevention of hardening off for winter, vole and other rodent damage to the trunk, keeping soil too wet, or repelling water.

Regular irrigation after planting encourages rapid root growth that is essential for tree establishment.  Trees provided with regular irrigation through the first growing season after transplanting require about 3 months (hardiness zones 9-11), 6 months (hardiness zones 7-8), or one year or more (hardiness zones 2-6) per inch of trunk diameter to fully establish roots in the landscape soil. Trees in desert climates may take longer to establish.  Trees that are under-irrigated during this establishment period (and most trees are) often require additional time to establish because roots grow more slowly.   Be prepared to irrigate through the entire establishment period, especially during periods of drought.

Irrigation also helps maintain and encourage the desirable dominant leader in the tree canopy on large-maturing trees.  Instead of a dominant leader, trees that are under-irrigated during the establishment period often develop undesirable, low, co-dominant stems and double leaders that can split from the tree later.

Unlike established plants, which do best with deep, infrequent irrigation, research clearly shows that recently transplanted trees and shrubs establish quickest with light, frequent irrigation.  For trees planted in spring or summer, provide one (cooler hardiness zones) to three irrigations (warmer hardiness zones) each week during the first few months after planting.  Daily irrigation in the warmest hardiness zones provides the quickest establishment.  Following the initial few months of frequent irrigation, provide weekly irrigation until plants are fully established.  With every irrigation, apply one (cool climates) to two (warm climates) gallons of water per inch trunk diameter (e.g. 2 to 4 gallons for a 2-inch tree) over the root ball only.  In most landscapes that receive more than 30 inches of rain or irrigation annually, if the mulch area is maintained weed-free, irrigation does not need to be applied outside of the root ball.  Never add water if the root ball is saturated.