Ulmus x hollandica is a group of trees resulting from the hybridization of U. carpinifolia and U. glabra. The classification of this group is somewhat confused. Not very useful as an American landscape tree. All are susceptible to Dutch elm disease and many formerly splendid specimen trees have died.
Height: 120 ft. to 120 ft. Width: 80 ft. to 80 ft.
low maintenance, seed start,
Early Spring to Late Spring
USDA Hardiness Zone:
5 to 7
AHS Heat Zone:
Not defined for this plant
Sun to Full Sun
5 to 7.5
Sandy Loam to Some Clay
Normal to Moist
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Conditions : Full to Partial Shade
Full shade means there is little or no light in the growing zone. Shade can be the result of a mature stand of trees or shadows cast by a house or building. Plants that require full shade are usually susceptible to sunburn. Full shade beneath trees may pose additional problems; not only is there no light, but competition for water, nutrients and root space.
Partial shade means that an area receives filtered light, often through tall branches of an open growing tree. Root competition is usually less. Partial shade can also be achieved by locating a plant beneath an arbor or lathe-like structure. Shadier sides of a building are normally the northern or northeastern sides. These sides also tend to be a little cooler. It is not uncommon for plants that can tolerate full sun or some sun in cooler climates to require some shade in warmer climates due to stress placed on the plant from reduced moisture and excessive heat.
Conditions : Types of Pruning
Types of pruning include: pinching, thinning, shearing and rejuvenating.
Pinching is removing the stem tips of a young plant to promote branching. Doing this avoids the need for more severe pruning later on.
Thinning involves removing whole branches back to the trunk. This may be done to open up the interior of a plant to let more light in and to increase air circulation that can cut down on plant disease. The best way to begin thinning is to begin by removing dead or diseased wood.
Shearing is leveling the surface of a shrub using hand or electric shears. This is done to maintain the desired shape of a hedge or topiary.
Rejuvenating is removal of old branches or the overall reduction of the size of a shrub to restore its original form and size. It is recommended that you do not remove more than one third of a plant at a time. Remember to remove branches from the inside of the plant as well as the outside. When rejuvenating plants with canes, such as nandina, cut back canes at various heights so that plant will have a more natural look.
Conditions : Normal Watering for Outdoor Plants
Normal watering means that soil should be kept evenly moist and watered regularly, as conditions require. Most plants like 1 inch of water a week during the growing season, but take care not to over water. The first two years after a plant is installed, regular watering is important for establishment. The first year is critical. It is better to water once a week and water deeply, than to water frequently for a few minutes.
How-to : Planting a Tree
Dig out an area for the tree that is about 3 or 4 times the diameter of the container or rootball
and the same depth as the container or rootball. Use a pitchfork or shovel to scarify the sides of the
If container-grown, lay the tree on its side and remove the container. Loosen
the roots around the edges without breaking up the root ball too much. Position tree in center of hole so that the best side faces forward. You are ready to begin filling in with soil.
If planting a balled and burlaped tree, position it in hole so that the best side faces forward. Untie or remove nails from burlap at top of ball and pull burlap back, so it does not stick
out of hole when soil is replaced. Synthetic burlap should be removed as it will not decompose like natural burlap. Larger trees often come in
wire baskets. Plant as you would a b&b plant, but cut as much of the wire away
as possible without actually removing the basket. Chances are, you would do more
damage to the rootball by removing the basket.
Simply cut away wires to leave several large openings for roots.
Fill both holes with soil the same way. Never amend with less than half original soil.
Recent studies show that if your soil is loose enough, you are better off adding little or no soil amendments.
Create a water ring around the outer edge of the hole. Not only will this
conseve water, but will direct moisture to perimeter roots, encouraging
outer growth. Once tree is established, water ring may be leveled. Studies show that mulched trees grow faster than those unmulched,
so add a 3"" layer of pinestraw, compost, or pulverized bark over backfilled
area. Remove any damaged limbs.
How-to : Sow Seed
Now is the preferred time to sow seed.
Diseases : Verticillium or Fusarium Wilt
Wilts may be contracted through infected seed, plant debris, or soil. This
fungus begins and multiplies during the cool, moist season, becoming obvious
when weather turns warm and dry. Plants wilt because the fungus damages their
water conducting mechanisms. Overfertilization can worsen this problem. Able to overwinter in soil for many years, it is also carried and harbored in
Prevention and Control: If possible, select resistant varieties. Keep nitrogen-heavy fertilizers to a minimum as well as
over-irrigating as they encourage lush growth. Practice crop rotation and prune out or better yet remove infected plants.
Pest : Mealybugs
Small, wingless, dull-white, soft-bodied insects that produce a waxy powdery covering. They have piercing/sucking mouth parts that suck the sap out of plant tissue. Mealybugs often look like small pieces of cotton and they tend to congregate where leaves and stems branch. They attack a wide range of plants. The young tend to move around until they find a suitable feeding spot, then they hang out in colonies and feed. Mealybugs can weaken a plant leading to yellow foliage and leaf drop. They also produce a sweet substance called honeydew (coveted by ants) which can lead to an unattractive black surface fungal growth called sooty mold.
Prevention and Control: Isolate infested plants from those that are not. Consult your local garden center professional or the Cooperative Extension office in your county for a legal insecticide/chemical recommendation. Encourage natural enemies such as lady beetles in the garden to help reduce population levels of mealy bugs.
Pest : Caterpillars
Caterpillars are the immature form of moths and butterflies. They are voracious feeders attacking a wide variety of plants. They can be highly destructive and are characterized as leaf feeders, stem borers, leaf rollers, cutworms and tent-formers.
Prevention and Control: keep weeds down, scout individual plants and remove caterpillars, apply labeled insecticides such as soaps and oils, take advantage of natural enemies such as parasitic wasps in the garden and use Bacillus thuringiensis (biological warfare) for some caterpillar species.
Pest : Scale Insects
Scales are insects, related to mealy bugs, that can be a problem on a wide variety of plants - indoor and outdoor. Young scales crawl until they find a good feeding site. The adult females then lose their legs and remain on a spot protected by its hard shell layer. They appear as bumps, often on the lower sides of leaves. They have piercing mouth parts that suck the sap out of plant tissue. Scales can weaken a plant leading to yellow foliage and leaf drop. They also produce a sweet substance called honeydew (coveted by ants) which can lead to an unattractive black surface fungal growth called sooty mold.
Prevention and Control: Once established they are hard to control. Isolate infested plants away from those that are not infested. Consult your local garden center professional or Cooperative Extension office in your county for a legal recommendation regarding their control. Encourage natural enemies such as parasitic wasps in the garden.
Diseases : Dutch Elm Disease
Dutch Elm Disease is caused by a fungus that is spread by elm
bark beetles infected with Ophiostoma ulmi. The disease was originally
brought to the United States via elm burl logs to be used for furniture veneer.
Beetles begin by feeding in the upper portions of a tree. As the fungus spreads,
toxins are produced which inhibits the water conduction in the tree.
Acute Dutch Elm Disease is rapid, leaves often wilting, curling and dropping
while still green. Death often occurs in just a few weeks. Chronic Dutch Elm
Disease is much slower. Though infected trees leaf-out in late summer, leaves
towards the top of the tree yellow and often drop. Closer inspection of limbs
reveals that wood beneath the bark is ringed with brown dots, or clogged
water-conducting tubes. Though trees may struggle for several years, they will
Prevention and Control - Unfortunately, very little can be done to prevent
the disease except to plant resistant varieties. Most will agree, early detection
is a must. Elms should be inspected each spring and again in late summer. Infected
trees must be destroyed immediately as elm bark beetles feed on healthy wood and
breed in dead or dying wood. Do not try to salvage any of the wood.
Glossary : Low Maintenance
Low maintenance does not mean no maintenance. It does mean that once a plant is established, very little needs to be done in the way of water, fertilizing, pruning, or treatment in order for the plant to remain healthy and attractive. A well-designed garden, which takes your lifestyle into consideration, can greatly reduce maintenance.
Glossary : Specimen
A specimen can be a tree, shrub, ground cover, annual, or perennial that is unique in comparison to the surrounding plants. Uniqueness may be in color, form, texture, or size. By using only one specimen plant in a visual area, it can be showcased. Specimen plants are accents in the landscape, just as statues, water features, or arbors.
Glossary : Deciduous
Deciduous refers to those plants that lose their leaves or needles at the end of the growing season.
Glossary : Seed Start
Seed Start: easily propagated from seed.
Glossary : Large Tree
A tree is considered large when it is over 30 feet tall.
Glossary : Flower Characteristics
Flower characteristics can vary greatly and may help you decide on a ""look or
feel"" for your garden. If you're looking for fragrance or large, showy flowers,
click these boxes and possibilities that fit your cultural conditions will be
shown. If you have no preference, leave boxes unchecked to return a greater
number of possibilities.
Glossary : Foliage Characteristics
By searching foliage characteristics, you will have the opportunity to look
for foliage with distinguishable features such as variegated leaves, aromatic
foliage, or unusual texture, color or shape. This field will be most helpful to you if
you are looking for accent plants. If you have no preference, leave this
field blank to return a larger selection of plants.