Care and How-To Articles - Trees and Shrubs
As winter fades and spring arrives, several things can be done to prepare the garden for the upcoming growing season.
Below are tips for the perennial garden, vegetable garden, annual containers, trees & shrubs, and lawns.
Gardeners can brighten up the last few weeks of winter by forcing branches of flowering trees and shrubs indoors. Forsythias, pussywillows, serviceberries, crabapples, magnolias, redbuds, and many fruit trees can be coaxed into early bloom indoors, helping revive the spirits of winter-weary Iowans.
Manure is the oldest fertilizer known to civilization. Many gardeners feel manure is superior to synthetic products. Careful and appropriate use of manure, especially in vegetables gardens, is important.
Iowa soils are very diverse and so are the chemical characteristics that make up these soils. Soil pH is one property that can vary widely across the state both naturally and due to how we manage the field or garden. It is also one of the most cost effective and easy to manage soil properties that can be modified to improve plant health and crop production.
Steps to Decrease Soil pH | Steps to Increase Soil pH | More Information
February and March is the best time to prune most trees and shrubs in Iowa. The absence of foliage at this time of year gives you a clear view of the tree and allows the selection and removal of appropriate branches. Also, when pruned in the late dormant season the walling-off, compartmentalization, or sealing of wounds can begin as soon as growth starts in the spring giving the tree the most time to recover from the pruning cut.
Iowa State University has many resources available to help with pruning all your woody plants.
There is something special about a healthy, well-maintained hedge. A symmetrical wall of green creates visual and physical limits in the landscape and provides a softer effect than wood or plastic materials. Hedges are an effective backdrop for flower beds and borders or may stand on their own in a diversity of shapes and sizes. Shrub plantings can be allowed to grow into a natural, informal hedge or they may be pruned (sheared) into a formal hedge.
Best Shrubs for Formal Hedges
Shrubs suitable for small hedges (less than 5 feet in height) include:
The keys to pruning trees and shrubs are a basic understanding of pruning techniques and knowing when to prune plants. It's also important to have the right tools. There are various types of pruning tools. The best tool for the job is determined by the size of the plant material and the situation.
When buying pruning equipment, select high-quality tools. Good, high-quality tools are not inexpensive. However, if they are used and cared for properly, they will perform better and far outlast the poor-quality, less expensive choices.
Oak trees are valuable assets in the home landscape. Occasionally oak trees need to be pruned for health, safety, and appearance reasons. Pruning oaks makes them more valuable to infection from the fungus that causes oak wilt. By pruning oaks properly, you can reduce that risk and keep trees healthy.
Young or newly-planted trees require special care to ensure their establishment and rapid growth. Young trees must be protected from the careless operation of lawnmowers and weed-trimmers, from vandals, and from harmful construction activities. They also must be given appropriate amounts of water and essential mineral elements (fertilizer) and may benefit from staking, trunk wrapping, and mulching. But pruning may be the most important post-plant maintenance task to perform on young trees if they are to live up to our expectations. The time and expense invested in training a young tree will always be much less than costly and time-consuming corrective pruning of neglected mature trees.
Pruning is a common garden task and proper pruning is important.
Many gardeners have questions regarding the pruning of trees, shrubs, fruits, vines, and other woody plants.
Get answers to your pruning frequently asked questions (FAQs) below.
https://www.iowapbs.org/shows/gardeningsteil/digital-short/3531/plant-shoppingIn spring, many gardeners will be at nurseries, greenhouses, and garden centers looking to buy plants. Selecting the right species and cultivar of a plant for the landscape by matching sun, water, soil, winter hardiness, and other growing requirements is important. Equally important is selecting high-quality plants. Below is advice on how to purchase high-quality plants from the garden center.
Growing trees from seed can be fun. However, the seed of most tree species won't germinate immediately when planted because they are in a dormant state. Dormancy must be broken before the seed can germinate.
Learn about the germination requirements for several specific tree species.
Heavy amounts of snow and ice on the branches of trees and shrubs can cause considerable damage. Improper removal of ice and snow can increase the amount of damage to trees and shrubs. Learn about how to manage ice and heavy snow on trees and shrubs.
An important aspect of pruning is knowing when to prune plants. Proper timing helps to insure attractive, healthy, productive plants. The proper time to prune trees, shrubs, and vines in Iowa is indicated below.
A shrub that flowers in winter? That sounds unlikely but witch hazels do just that - even in Iowa! Witch hazels (Hamamelis) are a group of shrubs that typically have the first (or last depending on what you are growing) blooms of the season in the garden.
During the holiday season, Christmas trees make appearances across Iowa and across the nation as part of the season’s celebration. But there’s plenty to learn about these popular trees. Below is information on the origins of the modern Christmas tree as well as facts and trivia about Christmas tree production.
The Origins of the Christmas Tree
Christmas trees are believed to have originated in Germany in the sixteenth century. There are several legends concerning the origin of the Christmas tree.
Cut Christmas trees are nearly synonymous with the holiday season. Fraser fir, white pine, Douglas fir, and other needled conifer trees are common species used for cut trees in Iowa.
When a cut tree isn’t feasible, rather than resorting to an artificial tree, there are several living Christmas tree alternatives. These not-so-common tree options are sometimes better sized, require less care, or live longer than the standard cut tree. More information about these living alternatives to the classic cut tree can be found below.
Many Americans decorate their home with an artificial, live, or cut tree for the holiday season. Learn more about some simple guidelines that will help ensure an enjoyable and safe holiday season, including where to buy cut trees, types of trees available, how to select, store, and care for the tree, as well as how to best recycle or dispose of it.
The predominate colors of the home landscape in late fall and winter are white and various shades of gray and brown. An excellent way to brighten the drab winter landscape is to plant evergreens (pine, spruce, fir, etc.) and trees and shrubs that possess brightly colored fruit. Growing plants with colorful fruit not only provide interest in the garden during the cold late fall and winter, they can also support wildlife such as birds.
The brightly colored fruit of many of the trees and shrubs will not remain throughout the entire winter. Extreme temperatures in mid-winter will eventually cause many of the fruit to turn brown or black. Hungry birds and squirrels will also devour the fruit. However, the display in late fall and early winter can be spectacular.
Deer, rabbits, mice, voles, and other animals can cause a lot of damage on trees and shrubs over the winter months. Prevention is key to managing these garden pests. By taking steps in the fall, you can prevent damage from occurring over the winter.
Cooler temperatures, crisp breezes, and beautiful fall foliage are some of the many reasons so many people love autumn. The yellows, oranges, reds, and purples seen on many deciduous trees and shrubs in fall come from compounds present in the leaves earlier in the growing season, but masked by the green chlorophyll in the leaves.
Crabapple trees are among the most widely planted ornamental trees in the upper Midwest, grown primarily for their colorful spring flowers, ranging from white/pink to red and reddish-purple.
Windbreaks are common sites around Iowa farms and acreages. A well-planned windbreak will moderate hot and cold temperatures, reduce dust and snow, save money in home heating costs, and add monetary value to your property.
Learn about siting, planning, planting, maintaining, and selecting the best tree and shrub species for your windbreak.
Many deciduous shrubs in the home landscape may be propagated by semi-hardwood cuttings.
Trees that can be propagated from semi-hardwood cuttings include willow, maple, tulip poplar, crabapple, and cherry.
Shrubs that can be propagated from semi-hardwood cuttings include rose, flowering quince. forsythia, and dogwood.
Time of Year to Take Semi-Hardwood Cuttings
Semi-hardwood cuttings are taken in mid-July to early fall from the matured current season’s growth. Cutting material should be firm with full-size leaves and has just become woody.
While spring is the traditional planting season in Iowa, late summer and early fall (mid-August to early October) is an excellent time to plant many landscape plants. Below is advice on fall planting of trees, shrubs, perennials, annuals, spring-flowering bulbs, lawns, and vegetables.
Trees & Shrubs | Perennials | Annuals | Bulbs | Lawns | Vegetables | More Information
Boxwood (Buxus sempervirens) is a dark green evergreen native to southern Europe and northern Africa. It usually grows to a height of three to four feet in Iowa's climate and is popular for borders and hedges because of its dense, dark green foliage. Boxwood requires fertile, well-drained soils and prefers wind protection if grown on an exposed site.
Winter can be tough on boxwoods in Iowa. Over the winter, boxwood may see extensive damage or even die. Sometimes, entire hedges will succumb. Exceptionally low temperatures are to blame in most cases. Boxwoods are marginally hardy in Iowa and can suffer from foliar burn and twig kill in severe winters in exposed locations. Leaves turn brown and twigs die back.
Newly planted trees can eventually add great color and valuable cover to any landscape. But winter’s harsh conditions can hamper, delay or completely derail their development. There are several things you can do to help these new additions to the landscape survive and thrive in colder temperatures.
Water Newly Planted Trees Until the Ground Freezes
The roots of trees continue to grow until the ground freezes in winter. If the weather is dry, continue to water newly planted trees until the soil freezes. Small trees usually require watering for one or two growing seasons. It may be necessary to periodically water large trees for three or four years.
If a tree, shrub, or perennial cannot be planted in its final spot before winter arrives, you will need to take steps to make sure it survives the winter while still in the container.
Container-grown plants should not be left outdoors above ground over the winter months. The roots of most trees, shrubs, and perennials are far less cold hardy than their aboveground stems or trunks. Container-grown plants are growing in relatively small amounts of potting soil. The temperature of the potting mix may drop into the single digits if container-grown plants are left above ground in winter. Single-digit temperatures may damage or destroy the root systems of plants.
Some plants in the landscape need a little extra protection to make it through the winter months. Here is what you need to know to successfully overwinter plants in Iowa.
When autumn arrives, several things can be done to prepare the garden for winter and the following growing season.
Perennials | Vegetable Garden | Annual Beds & Containers | Woody Trees & Shrubs | Lawns | More Information
When a summer heat wave arrives, it can be stressful for the plants and gardeners alike. The plants of your landscape will require a little more TLC to make it through periods of extreme heat. Below are a few tips to protect your lawn, garden, and landscape when temperatures soar.
Watering is one of the most frequent tasks performed in any garden or landscape. Proper watering utilizes water responsibly, reducing evaporation and runoff. There are many ways to make the process easier and better for the gardener and the plants. Use the tips below to water the perennials, annuals, containers, hanging baskets, lawns, trees, shrubs, and vegetables in your landscape.
Hydrangeas are popular shrubs for the home landscape. Their large, elegant flowers charm homeowners and visitors alike throughout the summer months. In the past decade, there has been an explosion of new cultivars with varying flower colors and shapes. With all this variety there is likely a hydrangea (or two) that will work in your landscape.
Several hydrangea species can be grown in Iowa. Two species (Smooth Hydrangea and Panicle Hydrangea) are easy-to-grow, reliable performers. The others can be a bit more challenging.
For shrubs to perform well in the landscape, home gardeners must prune them properly. Proper pruning helps maintain plant health, control or shape plant growth, and stimulate flower development.
Four species of hydrangea are commonly grown in Iowa. Pruning practices are based on the growth and flowering characteristics of each species.
Winter is a challenging time for trees and shrubs. Animals, wet snow, drying winds, sunscald, and deicing salts can damage trees and shrubs in the home landscape. Fortunately, steps can be taken to minimize damage to trees and shrubs in winter.
Newly-planted trees need active and frequent care during the entire establishment period. In USDA hardiness zones 4 and 5, the establishment period lasts about 12 months per inch of trunk diameter. For a two-inch caliper tree, this translates into a 24-month establishment period. Good cultural practices during this period help reduce transplant stress and create a favorable environment for tree growth.
Consistent and proper care during the establishment period is the single most important thing you can do to have success with your new tree.
Spring often gets all the attention when it comes to flowers, especially flowering trees. Yet, there are several tree species that bloom in early to late summer. In addition to their late bloom, these trees en have other ornamental features that make them deserving of a spot in your landscape.
Weedy vines can be some of the most difficult to control weeds in the garden. They are fast-growing, getting very large in a relatively short amount of time and often climb and cover other garden plants. These tenacious plants climb by twining, rambling, or utilizing specialized structures like tendrils or aerial roots. They are often botanically classified as eudicots and can be woody or herbaceous, perennial or annual. Examples of vining weeds include poison ivy, honeyvine milkweed, bindweed, and Virginia creeper. If left to grow, they can smother other plants, blocking light and killing the desirable plant.
Woody weeds are trees and shrubs that have woody plant tissue. They are perennial and typically classified as eudicots, although some may belong to other plant groups like gymnosperms (conifers). Examples of woody weeds include tree of heaven, bush honeysuckle, and poison ivy.
These weeds can be particularly difficult to manage, especially if they grow large.
Keeping ahead of weeds and controlling them when they are small is essential for good weed management. This requires persistence throughout the entire growing season to remove weeds as they emerge.
Anyone can plant a tree, but to ensure success, sound installation practices must be followed. Use this guide to plant any tree.
General Site Preparation | Planting Container-Grown Trees | Planting Bare-Root Trees | Planting Balled & Burlapped Trees | Planting with a Tree Spade | Post-Planting Care
Before you pick up the shovel, review your game plan one more time.
Organic mulches serve several important functions in gardens and landscape plantings.
These many benefits make the use of mulch very beneficial in a wide range of garden settings. When choosing which organic mulch to use, consider availability, cost, appearance, function, and durability.
Lilacs are one of the most cherished and adored of all flowering shrubs. They are noted for their beautiful blossoms and fragrance. Lilacs are available in a wide range of colors. Though they offer mainly one season of interest, their spring flower displays are greatly appreciated after a long, hard winter.
Learn about the selection and care of lilacs in Iowa.
After a long (seemingly endless) winter, most Iowans are eagerly looking forward to spring. Sure signs of spring are the emergence of tulips and daffodils, the greening of lawns, and the blooming of early spring-flowering shrubs. Though it may be hard to believe, the flowers of the following shrubs will begin to appear within the next few weeks.
There are about 45 species of dogwoods. Most are shrubs or small trees. Several dogwoods are valuable additions to home landscapes. A list of suggested dogwoods for Iowa, along with a brief description of each, is provided below.
Locations with moist to wet soils are not suitable for many shrubs. However, these sites are home to several native shrubs. A list of native wetland shrubs, along with a brief description of each, is provided below.
Shrubs are valuable assets to a home landscape. Shrubs are often planted for their ornamental characteristics, such as flowers, colorful fall foliage, or attractive fruit. They also can provide privacy, block views, and attract wildlife. For shrubs to perform well in the landscape, home gardeners must prune them properly. Proper pruning helps to maintain plant health, control or shape plant growth, and stimulate flower production.
Suckers are vigorous upright growing stems that form at the base of a tree or from the root system causing stems to appear inches or feet from the base of the trunk. They are problematic because they can reduce flowering and fruiting, alter the form of the tree, harbor pests and diseases, and look unsightly.
Learn about what causes suckers to form and how they can be managed in the home landscape.
Many deciduous shrubs in the home landscape may be propagated by softwood cuttings.
Trees that can be propagated from softwood cuttings include willow, maple, ginkgo, elm, crabapple, linden, birch, sweet gum, and redbud.
Shrubs that can be propagated from softwood cuttings include lilac, forsythia, weigela, dogwood, ninebark, and viburnum.
Time of Year to Take Softwood Cuttings
Softwood cuttings are taken in late May through early July from the current season’s growth. Cutting material should be flexible but mature enough to snap when sharply bent.
During the cold, gray days of winter, most Iowans look forward to the vibrant colors of spring. The explosion of colors in the home landscape in spring include tulips, daffodils, Siberian squill, other spring-flowering bulbs, the greening of lawns, and flowering trees. The following are excellent small, spring-flowering trees for the landscape.
Trees are a vital part of the home landscape. Trees provide beauty, shade, and habitats for wildlife. They can also screen unsightly views, provide privacy, reduce noise pollution, lower utility bills, and provide many other benefits. The most common way to establish trees in the home landscape is to purchase balled and burlapped or container-grown plants at local garden centers and nurseries.