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2. Perennial Plant of the Year: Lenten Rose
By Kelly Feehan, UNL Extension Educator
If you need a perennial to grow in a shady site, and you’re not interested in hosta, consider Lenten Rose, or Helleborus x hybridus.
Maybe you need a plant that deer, and possibly even rabbits, do not like to eat? Are you trying to conserve water in your landscape? Lenten Rose could still be a good choice.
The perennial plant association has named Lenten Rose as the 2005 perennial of the year. This spring blooming plant is hardy to zone 4 and will do fine in our winters. When planted in shade, it will tolerate our hot summers.
Helleborus x hybridus Orientalis
Image from Bluebird Nursery,
www.bluebirdnursery.com
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Helleborus 'Ivory Prince'
Image from White Flower Farm,
www.whiteflowerfarm.com |
If you plant Lenten rose in a shady site with well drained soil and wait a couple of years for the plant to establish, you’ll be rewarded with early spring blossoms and unique shaped, green leaves for most of the year because the plant is evergreen.
Like most perennials, Lenten rose requires a well drained soil. One that is high in organic matter or a sandy loam soil. Perennials are subject to crown and root rots which are promoted by poorly drained or overly wet soils.
Once established, Lenten rose will bloom in early spring for up to two months with flower colors ranging from white to plum and red, pink and yellow. The flowers are buttercup shaped and hang downward.
The unique foliage is ornamental for most of the year. The individual leaves are leathery and made up of 7 to 9 leaflets that look like flat umbrellas. Leaves will look tattered by winters end and, like all herbaceous perennials, should be cut back to make room for new growth.
Mature plants form clumps that grow 18 to 24 inches tall and 24 to 30 inches wide. Once the roots are established, Lenten rose is drought tolerant, making them a good choice for water conserving gardens.
A downside to Lenten rose, which can actually become a positive, is people with sensitive skin may develop dermatitis after long term exposure to the leaves. The alkaloids in the leaves that cause this are also the reason deer, and possibly rabbits, do not like to eat Lenten rose.
Lenten rose is best to grow from transplants as plants do not come true from seed. The plants may be divided, but divisions can take some time to rebloom and plants are fine if left undivided for years. Seedlings are produced in the garden that can be transplanted, although flower color may vary.
Source: Perennial Plant Association
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3. April Lawn Questions
By Kelly Feehan, UNL Extension Educator
Warm weather triggers a rash of calls to UNL Cooperative Extension. Common questions received in April are about power raking, applying herbicides for crabgrass, and moles.
When is the best time to power rake lawns? Power raking removes excess thatch from lawns. Thatch is a reddish brown mat of roots, rhizomes and stems found between the soil and green grass. It can only be seen and measured by cutting and removing a wedge of sod from turf.
A thatch layer up to one-half inch is beneficial. It protects the plants growing point from temperature extremes and foot traffic. When thatch exceeds one-half inch, it becomes harmful. Fertilizer and pesticides tie up in thatch and root growth occurs in thatch rather than soil.
Power raking causes some damage to lawns and stirs up weed seeds. It should only be done when thatch exceeds one-half inch, the soil is not too wet, and when 30 good growing days will follow before stressful weather (hot or cold) arrives.
If power raking is needed, April or September are the recommended months. If power raking can be delayed, September is preferred. Preemergent herbicides, such as those applied for crabgrass in spring, need to be applied after power raking or their effectiveness will be reduced.
Should crabgrass herbicides be applied before April 15? The ideal window for applying preemergent herbicides for crabgrass control is April 20 to May 5. If your main goal is to control crabgrass, and you apply your own fertilizer with crabgrass preventer, wait until late April.
Waiting until late April allows soil temperatures to warm so root growth is promoted by fertilization along with top growth. Waiting also provides a longer season of control for crabgrass so only one herbicide application is needed.
Crabgrass is a warm season grass. The majority of seed germinates after soil temperatures reach and remain at 60 degrees Fahrenheit. Soil temperatures in Nebraska do not reach this level until some time in May.
Is there anything new for controlling moles? Unfortunately, there isn’t. For control of moles, trapping or applying a repellant containing castor oil are still the two main recommendations.
Research has shown what does not control moles. These include poison baits or peanuts, gum, sonic devices, and applying insecticides to kill the insects the moles are feeding on.
Moles tunnel in lawns while searching for and feeding on insects. Signs of moles are raised tunnels in the lawns and small, cone-shaped mounds of soil.
If you need to control moles, call or stop by your local Extension office for a copy of our Mole Nebguide. The Nebguide provides good tips for success with traps and repellants.
Moles and Their Control, http://ianrpubs.unl.edu/Wildlife/g1288.htm
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4. Vines in the Landscape
By Kelly Feehan, UNL Extension Educator
Vines have many uses in the landscape. They create outdoor walls and ceilings when supported by an arbor or trellis. Grown as a ground cover, they become an outdoor carpet.
When used as a wall or ceiling, they provide fairly quick shade and privacy and soften the hard lines of structures like a gazebo or a fence. As ground covers, they fill in the base of leggy plants, act as a mulch, or prevent soil erosion on sloped areas.
Vines also provide aesthetics such as blossoms, fall color, winter color, interesting seed heads, fragrance and attracting songbirds.
When selecting a plant to grow as a vine, check to see it’s adapted to the site where it will be planted, what size and sturdiness of structure is needed to support the vine, and how the vine climbs.
Vines climb by twining, clasping, or clinging. Some plants, such as rambler roses, will not climb on their own and need to be tied to the structure.
Twining vines climb by wrapping stems around supports. Clasping vines wrap curly-cue tendrils around their supports. Both types climb best on fairly thin surfaces such as wire, string, netting, small poles, lattices or chain link fences.
Despite climbing best on thin surfaces, it’s still important to estimate the eventual size and weight of the vine. Be sure to provide sturdy enough support to bear the weight of the mature vine.
Clinging vines climb by adhering to supports with aerial roots or adhesive like pads. Some vines have tendrils and adhesive pads. These vines climb best on flat, but rough surfaces such as stone, brick or rough bark.
Clinging vines are best not used on wood siding. Aerial roots could damage wood siding and when wood buildings need painting, aerial roots or adhesive pads are difficult to remove.
Some fast growing, vigorous vines for our area include Kolomikta actinidia (twining), Elegans ampelopsis (clasping), sweet autumn clematis (clasping), Baltic Ivy (clinging), Hall’s, Mandarin and trumpet honeysuckles (twining), Virginia creeper (clasping and clinging), grapes (twining) and many climbing roses (varies).
Slower growing, more refined vines for our area include Jackman clematis (clasping), wintercreeper (clinging), Boston ivy (clasping and clinging), glory vine (clasping) and some types of roses (varies).
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5. Tree Selection and Allergies
By Kelly Feehan, UNL Extension Educator
When selecting trees to plant around the home, it is common to select seedless trees because they create less litter. If you have plant allergies, you may want to reconsider and ask yourself what is more of a problem, the tree seeds or your allergies?
A seedless tree is a male tree whose flowers produce pollen, the allergen that triggers many allergy and asthma incidents. Seeded trees have female flowers and do not produce pollen or they act as traps for the pollen the tree produces.
To better understand, here’s a botany lesson on plant sexes. Plants are monoecious or dioecious. Monoecious plants have male and female flowers on the same plant. Dioecious plants have either male or female flowers, but not both.
Male flowers are staminate flowers which produce pollen. Female flowers are pistillate and contain an ovary which develops into a fruit or “tree seeds” when pollinated. When we buy seedless trees, we are buying dioecious male plants.
From an allergy perspective, dioecious male trees are the worst because they only produce pollen and their pollen is usually windborne. Dioecious female trees are best because they produce no pollen. Monoecious plants produce pollen, but because they also have female flowers some of the pollen is trapped.
For convenience, and because consumers dislike plant litter from tree seeds, thousands of seedless varieties have been developed for the market. As our landscape tree plantings become predominately seedless trees, the natural mix of male and female trees have been altered and pollen loads have increased.
Since a pollen producing tree next to a home can create ten times more exposure than a tree one or more houses away, selecting a tree that does not produce pollen may be a wise choice if you are an allergy sufferer.
The USDA has rated trees on a plant allergy scale that rates trees from one to 10 with one being a being a female, pollen-free plant and 10 being a male, allergenic, airborne, pollen-intensive plant. The scale used was developed by California horticulturist Thomas Ogren.
Some of the commonly planted dioecious male trees with a rating of 8 to 9 include Autumn Blaze maple, Patmore green ash and Northwood maple. Common monoecious trees with a rating of 7 to 8 include all Lindens, Oaks and Sugar maples.
Some cultivars that are dioecious females with a rating of one include Autumn Blaze white ash, Red Sunset maple, Autumn Fantasy maple and Noreaster poplar as well as pollen-free, seeded green ash, red maples, or silver maple.
Source: University of Minnesota Living On A Few Acres newsletter.
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6. Tree Planting and Arbor Day
By Kelly Feehan, UNL Extension Educator
In Nebraska, Arbor Day is celebrated the last Friday in April. This year, April 29 is the day of honor and much tree planting will take place from now through May.
Planting trees correctly determines the long term success and health of trees. If planted incorrectly, or improper post planting care is provided, a tree may die or be less vigorous and more susceptible to disease and insects throughout its life.
Planting trees too deep is one of the main reasons trees die or fail to grow vigorously. In some cases, too deep planting can explain why one tree in an area has a pest problem while nearby trees avoid the problem.
To avoid planting trees too deep, begin at the garden center or nursery. When buying a tree, look for the trunk taper or root flare. This is a slightly flared area at the base of the trunk and just above the roots.
If trees are balled and burlapped or growing in a container, the trunk taper should be visible just above the soil line. This indicates the tree was not planted too deep; and, will help you avoid planting the tree too deep in its permanent location.
When digging the planting hole, do not the dig the hole any deeper than needed to plant the tree so its trunk taper is just above the soil line. Do not dig the hole to loosen the soil beneath the root ball. After planting, loose soil will settle and the tree will end up being planted too deep.
The hole should be dug wider than the root ball. For two foot diameter root balls, dig a four foot diameter hole if space allows. Since tree roots grow outward and not downward, loosening the soil on the sides of the root ball encourages root growth.
Before planting a tree, check the root ball for heavy encircling roots and cut larger roots growing in a circle on the outside of the root ball. If not cut, these roots could continue to grow in a circle and eventually girdle, or suffocate the tree.
Carefully set the tree in the hole on top of undisturbed soil and at the correct depth. The tree will be planted at the correct depth if the trunk taper is visible just above the soil line. Be sure to remove all containers, burlap, and wires.
If the burlap and wires cannot be removed without the soil ball falling apart, set the balled and burlapped tree into the planting hole and then cut the wires and cut away as much of the burlap as possible.
Backfill the hole with native soil and not amended soil. Add a few inches of soil, then water each layer to help settle the soil and avoid air pockets in the planting hole.
As a general rule, most Nebraska soils are fertile enough for tree growth. A starter fertilizer, or one high in phosphorous, could be worked into the soil prior to planting and this may encourage faster root growth.
Avoid high nitrogen fertilizers or fertilizers with fast release sources of nitrogen, such as ammonia. These can burn roots or result in succulent leafy growth at the expense of roots.
After planting, place a two to four inch layer of mulch in a four foot diameter ring around the base of the tree. Do not use a deeper layer or pile mulch against the trunk. Mulch conserves soil moisture, maintains a cooler soil temperature, suppresses weeds, and protects trees from lawn mowers and weed trimmers.
Depending on your soil type, newly planted trees require 3 to 5 gallons of water per week. After watering, check to see the soil has been moistened at least 8 to 12 inches deep and water again only after the soil dries slightly.
Overwatering is a common killer of young trees. Tree roots need oxygen to grow. If soils remain saturated for too long, the water displaces soil oxygen and tree roots stop growing or die.
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7. Livestock Fencing
By Don Janssen, UNL Extension Educator
Fencing costs are one of the most expensive aspects of livestock grazing. The type of fence constructed greatly impacts the cost per foot as well as total cost of the fence. In addition, the shape of the paddocks affects the amount of materials needed and labor required for construction.
The following publication compares the costs of building a 1/4-mile (1,320 feet) straight perimeter fence with woven wire, barbed wire, high-tensile non-electric, and high-tensile electrified, and temporary interior fencing.
Estimated Costs For Livestock Fencing
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8. Small Scale Poultry Housing
By Don Janssen, UNL Extension Educator
Small scale poultry coops seem to be built in almost every possible shape and size. Those building a new coop often ask for plans for the perfect chicken coop. However, few plans for small poultry houses are available. Many existing buildings can easily be adapted to accommodate poultry. Poultry housing can be as crude or elaborate as you wish to build as long as you provide some basic needs.
Check out this site:
Small Scale Poultry Housing
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9. Integrated Pest Management and It's Time To Control:
Sphaeropsis tip blight, Anthracnose, Cedar apple rust, Apple Scab and Spruce spidermites
By Kelly Feehan, UNL Extension Educator
As the growing season begins, insects, diseases and weeds become active. Now is the time to begin control of some tree and turfgrass pests (listed below); but only if the pest is present and control is needed to reduce unacceptable damage.
A common reaction to pests or pest damage is to apply a pesticide such as an insecticide, fungicide or herbicide. With concerns about potential environmental risks related to pesticides, it’s important to manage pests in a way that minimizes these risks.
To effectively and responsibly manage pests, follow the steps of Integrated Pest Management (IPM). These steps are pest monitoring; positive pest identification; determining if control is needed; selecting control methods; and correctly using the control method at the right time.
On a regular basis, check garden and landscape plants for signs of pests. Early detection allows control methods to be used before a problem becomes too serious or it’s past the time for control methods to be effective.
Pest identification allows for selection of the most effective control method. The symptoms different pests cause can be similar to one another. Positive identification prevents mistakes like applying an insecticide for damage from environmental stress or a disease.
All pests do not require control. The damage some pests cause is aesthetic only and does not damage long term plant health. Violets in the lawn can be viewed as a weed or as an ornamental. Some pests require control only when their numbers reach a certain population level.
If it’s determined control is needed to reduce unacceptable damage, consider a variety of control options. IPM promotes the use of cultural, mechanical, biological, and chemical controls. Pesticide use is recommended only when needed and in the least-toxic formulation that is effective against a pest.
For control methods to be effective in reducing pests or their damage, they must be used correctly and at the right time. This is especially true of pesticides. Following are the tree and turfgrass pests for which pesticides, if the pest is present and this control method is chosen, need to be applied in April.
- Fungicides for Sphaeropsis tip blight of pines need to be applied during the third week of April and 10 to 14 days later.
- Fungicides for fungal leaf diseases such as anthracnose on shade trees and cedar apple rust or apple scab on crabapples and apple trees need to be applied at leaf bud break and repeated as the label states.
- Insecticides for control of worms in fruit trees are applied at petal drop and repeated as listed on the label.
- Spruce mites on evergreens begin to hatch in April and May. Using the white paper test, monitor evergreens for spruce mites and begin insecticide or insecticidal soap applications when spruce mites can be found.
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10. Pruning Roses- Shrub, Climber & Rambler and Hybrid Tea
By Sarah Browning, UNL Extension Educator
Pruning Shrub Roses
Many gardeners are hesitant to prune landscape roses, fearing they will do something wrong and damage or kill the plants. However, pruning provides several benefits including improved flower quality. Pruning gives plants a better shape and maintains a plant size that fits into the landscape. Pruning also improves plant health by increasing air movement around and through plant foliage.
Shrub roses should be pruned in early spring, late February or March, preferably while still dormant or pruning can be left until early spring, just as the new growth begins to emerge.
Following a sequence of steps when pruning can make the process seem less complicated. First, remove any dead, diseased or damaged branches. Remove dead wood to the nearest healthy bud. Pith (located in the center of the stem) should be creamy white on healthy, live wood, not brown or gray. If the inside of the stem is brown, prune the cane back farther. Make the cut at least one inch below the dead area. If there are no live buds, remove the entire branch or cane to the base of the plant. Examine canes carefully for canker (a darkened, sunburned-looking area) or other diseased areas. If disease is found, cut down to a good bud at least one inch below any evidence of disease. Prune to where the pith is healthy or to the plant’s crown.
Next, remove up to one third of the oldest, woodiest stems, cutting them back to the plant’s crown. This encourages the growth of new, vigorous stems from the plant crown and eliminates the development of many old, woody branches with poor flower production. It also increases air circulation through the plant, reducing potential for disease problems.
Finally, shape the plant as needed keeping in mind that shrub roses should not have more than 1/3 of their canopy height removed.
Popular shrub roses that perform well in the landscape include older, traditional varieties like ‘The Fairy’, ‘Frau Dagmar Hastrup’, ‘Harison’s Yellow’, ‘Seafoam’, ‘Meidiland’ and ‘Hansa’. Newer varieties include ‘Nearly Wild’, ‘Knock Out’ and ‘Pink Knock Out’.
Pruning Climbing & Rambling Roses
In the first two or three seasons after planting, new climbing and rambling roses should receive little pruning, except to remove any winter-killed wood in spring. In subsequent years, prune ramblers and vigorous climbing roses soon after flowering. Be sure to remove all suckers, especially on grafted roses, to prevent the rootstock from overgrowing the grafted portion of the plant. (Remember that most named varieties of roses are grafted onto a species rose rootstock.)
Most climbing roses bloom on current season growth, and may bloom once or be repeat bloomers. These roses are often derived from hybrid tea roses and are not particularly vigorous, usually requiring little yearly pruning except to remove winter-killed wood, dead, diseased, or weak growth and old, unproductive canes. Pruning should be done in spring before new growth occurs. ‘Joseph’s Coat’, ‘Handel’ and ‘Don Juan’ are a few varieties of climbing rose.
Some varieties of climbing roses, often identified by the word ‘climbing’ in front of the variety name, originated as a tall sport from a hybrid rose variety, such as ‘Climbing Peace’. These roses should not be pruned back heavily within the first two or three years after planting, or they may revert to the bush growth form. Throughout the summer spent flowers on repeat blooming climbers should be cut back to the first set of five-leaflet leaves to allow for reblooming.
Climbing roses derived from Rosa wichuraiana, including ‘Alberic Barbier’, ‘Silver Moon’ and ‘May Queen’, bloom on one-year old wood, do not repeat bloom and tend to be very vigorous plants. One method of pruning these roses is to cut blooming canes back to the ground after flowering and leave any newly emerging shoots to grow and bloom the following summer.
Rambling roses are vigorous plants that produce small clusters of flowers only once during the growing season. ‘Excelsa’, ‘Dorothy Perkins’, ‘American Pillar’, and ‘Veilchenblau’ are a few examples of rambling roses. Rambling roses produce much more growth from the crown than climbing roses, and can easily become a tangled mass of branches if not pruned properly. Nearly all ramblers produce flowers only on second-year wood and should be pruned in summer after blooming. Begin by removing diseased and dead canes. Next, remove the older, gray-colored canes since most canes will decrease in flower production after only 2-3 years. Also remove weak, thin-diameter canes leaving only the most healthy, vigorous canes. Cut lateral (secondary) branches back to 8-10 buds and shape the plant as desired.
Pruning Hybrid Tea Roses
Hybrid tea roses are the most popular garden rose, and require regular pruning to maintain vigorous growth, flower quality and quantity, and to remove dead, diseased, weak or broken branches. Hybrid tea roses have large flowers produced singly on long stems or in clusters and include common varieties such as ‘Peace’, ‘Sterling Silver’, ‘Double Delight’, ‘Mister Lincoln’, and ‘Tropicana’.
Hybrid tea roses bloom on new growth, so are pruned in spring just as the buds begin to swell. The amount of wood removed depends primarily on how much winter injury has occurred however, pruning can also be used to manipulate the size, timing and number of flowers that a plant produces in the coming summer months. Like any blooming plant, rose leaves generate the energy resources required for flower development and it takes 25-35 leaves to create and bring into bloom one rosebud. Consequently, removing more or less foliage through pruning will affect the amount of flowers each plant can generate.
In Nebraska moderate to light pruning is preferred. This technique will produce slightly smaller flowers in greater numbers and is achieved by pruning plants back to 12-24 inches in height or about half the branch length in spring. Completely remove dead, diseased, weak or broken branches by cutting them back to the crown. Also inspect the plant for crossing branches, and remove one so that they do not rub against each other and cause wounds.
Severe or ‘hard’ pruning will cause hybrid tea roses to develop larger flowers, but blooming is delayed and fewer flowers will be produced overall. Severe pruning is recommended only on plants for exhibition or show. In spring, plants are pruned back to 6-8 inches in height. Select the strongest 5 or 6 canes and cut them back to an outward facing bud. Remove all other canes back to the crown.
A few last things to keep in mind include the following. Use sharp, scissor-type pruners to make the cleanest cuts. Make pruning cuts at about a 45-degree angle to facilitate shedding of water from the cut stubs. Always cut branches back to an outward facing bud and remove suckers originating from the rootstock. Deadheading, or removing spent blooms, will keep your plants blooming all summer. Cut the stems back to the first 5-leaflet leaf beneath the old flower. Finally, pruning too early in the season can cause plants to initiate growth that is damaged by late frosts, so don’t be tempted to prune too early.
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