Year-Round Gardening: The Right Size Plants for Your Colorado Landscape | Way of life


Before purchasing a tree, shrub, or perennial, homeowners should research the mature size of the plant to allow enough room for that plant to grow in a healthy environment. Plant labels often include suggested spacing. Choosing plants that are too large for the intended site can have negative or even disastrous consequences.

Consider trees first. This Honeylocust tree from the local nursery that is 10 feet tall when purchased could eventually reach 60 feet tall and wide. When selecting a tree, make sure it will fit into the available growing space without pruning. Allow your tree enough root space so that enough water and oxygen is available to the tree throughout its life. A mature tree should not obstruct a desirable view of the interior of the home, impede access to the front door, obstruct a driver’s visibility at an intersection, or touch overhead power lines. Tree roots can damage underground power lines, septic tanks and foundations, and can push up concrete sidewalks and driveways if planted too close. To estimate the impact of the mature width of a tree canopy, place pipes, strings or stakes in a circle halfway the mature width of the tree. This will let you know if the tree will be the right size when mature.

The mature size of a tree is also important for fire mitigation. Will that tree you plant end up having branches overhanging the house in 20 years? To avoid this, plant the tree further from the house or choose a smaller tree for the site.

Homeowners also often underestimate a shrub’s size at maturity. Shrubs can grow up to 20 feet tall and can spread up to 15 feet. Shrubs planted too densely may receive more shade or require more frequent pruning. If the shrubs in your landscape are too close together, consider removing one or more to allow more room for others. If you are planting shrubs for a hedge, you can bring them closer together to provide a denser screen for privacy or a windbreak. Hedge plants that will reach 3 to 4 feet tall at maturity should be spaced about 18 inches apart, while taller hedge plants should be planted 3 to 4 feet apart.

It is also important to leave enough space between your perennials. Although you may be tempted to place plants close together to make your beds look fuller, this can result in plants crowding together when they reach maturity. Overcrowding of plants can lead to poor air circulation between plants, making them more susceptible to diseases such as powdery mildew. While waiting for your perennials to mature, plant annuals for early growing seasons in bare spots.

By designing your landscape with the mature size of your trees, shrubs and perennials in mind, you can provide a healthy environment for your plants and avoid costly mistakes in the future.

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