The fastest growing evergreen shrub is arborvitae Green Giant. It pushes out 3 to 5 feet of new growth per year under good conditions. It reaches 40 to 60 feet tall at full size and fills in thick enough to block views within two to three growing seasons.
Most people shopping for fast growing privacy shrubs want a green wall between them and their neighbors fast. Green Giant delivers on that promise quicker than almost anything else. Leyland cypress comes close at about 4 feet (1.2 meters) per year. But it tops out at 100 feet (30 meters) tall and needs at least 15 feet (4.5 meters) between each plant. That size causes problems in most suburban yards.
I planted a row of six Green Giants along my back fence four years ago. They went in at 4 feet tall and now stand over 18 feet high. The two that got rich compost and drip watering grew almost twice as fast as the two on the end. Those end plants sat in compacted clay with no extra water. Soil and watering make a huge difference in how fast these quick growing evergreens fill out.
When I first put them in, I figured fast growth was all upside. I was wrong. These plants don't stop growing once they hit the height you wanted. You'll need to prune Green Giant at least twice per year to keep it from turning into a tree. Leyland cypress can get so tall that trimming the top needs a pro with a bucket truck. Ice storms and heavy snow snap branches on fast growers more often than on slower, denser species.
Think about your yard's size before you commit to a speed demon. A quarter-acre suburban lot can't handle Green Giant or Leyland cypress for long. Within five years they'll tower over your roof. Arborvitae North Pole grows at a steady 1 foot per year and tops out around 10 to 15 feet. That fits most setback rules and fence height limits.
Check your property lines and measure the gap to your fence, house, and power lines before planting. Give each shrub at least half its mature width in spacing from structures. A little patience with a moderate grower beats the cost of removing a monster that outgrew your yard in three seasons.
In my experience, the best approach is planting a moderate grower and feeding it well. A well-fed Skip Laurel or North Pole arborvitae fills in fast enough for most people. You get your privacy screen without the headache of fighting a plant that never stops growing taller and wider.
Read the full article: Best Evergreen Shrubs for Your Garden
