Selecting new plants for your landscape can be a daunting task, particularly if you are fairly new to gardening. With so many plants to choose from, it can be difficult to decide which ones will work for your yard. Since shrubs can be an expensive and permanent investment, you might worry about making a costly mistake. Fortunately, it’s quite easy to be successful as long as you do a little bit of research and spend some time carefully considering the growing conditions in your yard and garden.
Before bothering to spend too much time deciding which shrubs might look nice in the landscape, you’ll need to establish your hardiness zone. The USDA has developed a plant hardiness zone map that is based on the average annual minimum winter temperature, divided into 10°F zones. Most of New Hampshire falls in zone 4 (-30 to -20°F) and zone 5 (-20 to -10°F). If you live in a zone 5 area, then zone 5 or lower shrubs should be able to survive the winter without damage.
Simply looking at where your property falls on the hardiness zone map isn’t always enough to determine which plants will do well in a given location. Considerably warmer and colder spots, called “microclimates”, exist within each zone. For example, areas near buildings or on south facing slopes may be a zone or two warmer. In addition, roots, stems, leaf and flower buds can be hardy to varying temperatures. It’s quite common for extreme cold to damage flower buds or shoots but leave the root system intact.
When planting shrubs you also need to consider site conditions. Sun exposure can have a big impact on growth, including flower and fruit production. Many flowering shrubs such as lilacs and forsythia produce more blooms when they are grown in full sun. These shrubs also tend to have denser growth when grown in areas with more sunlight. If your landscape is partially shaded, you’ll want to look for plants that prefer filtered sunlight such as rhododendrons or mountain laurel.
It may go without saying that shrubs also have different soil requirements. Pay attention to soil moisture and drainage, and get your soil tested to determine fertility and pH. While some shrubs will do well in dry or waterlogged soils, others only grow properly in consistently moist, well-drained soils. pH can also have an influence on plant health. In particular, acid loving shrubs like azaleas and blueberries will fail to thrive or display nutrient deficiencies if they are planted in soil that is too alkaline. If your soil does not fit the pH requirements of the shrubs you want to grow, you will need to amend it before planting (based on soil test results).
It is incredibly important to pay attention to the height and width of mature shrubs. Choosing plants that will fit within the size limitations of your site will ultimately save a lot of headache and maintenance. Trying to limit the height of large shrubs through repeated pruning is not only a hassle but also often results in shoddy looking specimens. Planting an eight-foot shrub in front of a window is never a good idea when there are plenty of other smaller, more appropriate options to choose from. And, don’t forget that cultivars of a shrub are often smaller or have different growth habits than the wild species. For example, hinoki falsecypress (Chamaecyparis obtusa) will grow to be 50 to 75 foot tall tree in its natural form. However, there are many cultivars of this plant that stay very small and are suitable for foundation plantings and perennial borders, such as Chamaecyparis obtusa ‘Densa,’ which only grows to a mature height of 1-2 feet. Thus, it is very important to research the exact cultivar or variety you plan to grow in order to know if it will be appropriate for your landscape.
Last but not least, you’ll want to think about what your new shrubs will contribute to your yard. Ask yourself whether you are you looking for features such as early spring blooms, interesting foliage or wildlife value. Regardless of what your goals are, you’ll likely have a number of suitable options to choose from, and the staff and Master Gardener volunteers at UNH Extension’s Infoline are happy to help you pick out shrubs that will thrive in your landscape for years to come.
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Got questions? The Ask UNH Extension Infoline offers practical help finding answers for your home, yard, and garden questions. Call toll free at 1-877-398-4769, Monday to Friday, 9 a.m. to 2 p.m., or e-mail us at email@example.com.