Revolutions don’t happy often in the world of gardening, but back in the 1990s there was one – the arrival of Thuja Green Giant. The timing couldn’t have been better, because all across the country there were old hedges that needed replacing. Most of them were of an older fast-growing evergreen, Leyland Cypress, that had been very popular indeed following its introduction in the 1970s, as the hedging and screening plant everyone was planting. Those hedges were 30-years old or more, and many were beginning to suffer from disease, and becoming overgrown.
So when nurserymen saw Thuja Green Giant growing at the National Arboretum in Washington, DC, they were enthusiastic. The trees they saw had grown to 30 feet in about 30 years – much faster growth than any other evergreen, and they were impressive, dense, upright specimens about 12 feet across. No wonder those growers were impressed. They set to work propagating plants, and letting customers know that this plant was ideal to replace those old hedges, or for planting new ones.
Today, 20 years later, it is clear that their faith in this tree was not misplaced. It remains the number-one choice, and there are millions of satisfied gardeners all across the country who have used it to bring privacy and beauty to their gardens. So is this the tree for you? Here are some simple questions to ask yourself to find out.
How Big a Hedge do I Want?
All hedging plants are not equal in size – even if they look that way at the nursery. So the first thing is to calculate how tall a hedge you need. It always makes sense to go with the shortest possible one, to reduce clipping, especially to reduce the need to be up tall ladders and on scaffolding. Why grow a 15-foot hedge, when a 10-foot one would have done the trick? There are mathematical ways of calculating this, but the easiest way is to use a tall rod – some bamboo poles tied together for example, and with a helper holding it, see how tall a hedge you need to give you privacy or block that unsightly view. Hold up different heights until you can see coverage from the critical spots in your garden, or from those ground-floor windows. If it is upstairs windows you want privacy in, a hedge will rarely work, unless it is very tall, and therefore hard to manage.
If course, if you have plenty of room, you don’t need to clip, especially with a sturdy plant like Thuja Green Giant, and then the sky is the limit. Even then, consider shade. In winter a tall hedge can cast a 50-foot shadow, and that may not be what you want, so that is another reason why excess height is not desirable.
If you end up wanting a hedge less than 6 feet tall, then consider a smaller evergreen, like Emerald Green Arborvitae. This is also a to-choice if you live in zone 4 or cooler, as this native tree is extremely hardy, and grows well even up in Canada. If you live in zone 5 or warmer, and want a hedge taller than that, then Thuja Green Giant is your go-to plant. In very dry areas, if you don’t have much or any irrigation, then look to upright Junipers instead, as they are renowned for drought-resistance.
What is My Garden Like?
Thuja Green Giant is a tough plant, and it will grow almost anywhere. But it does have some needs, so check the parameters of the area you are planning to plant in. Is it sunny most of the time, or shady, perhaps beneath trees? For good growth with Thuja Green Giant, you want at least 6 hours of direct sunlight between spring and fall, and of course the more there is, the denser your plants will grow. If the area is beneath trees, then consider a more shade-tolerant hedge plant, like Yew, Holly, or, for smaller hedges, Boxwood.
The second consideration is the soil. Is the area always wet, even a week after rain? Wet, boggy conditions are not suitable, so again, another choice, is needed. The Dawn Redwood is the perfect evergreen for wet places, although it does become bare in winter. An alternative approach is to raise up the soil for your hedge into a low mound, at least 6 inches above the level of the surroundings, and 3 feet wide. As you throw up the soil, you also automatically create a drainage ditch around the mound, which will carry away the water that drains from the soil. Planted on a mound like this, Thuja Green Giant will thrive, using the wetter soil around it in dry periods.
The only consideration with your soil is its type. Is it sandy, loamy or clay? Although a lot is sometimes made of soil types, and certainly some plants prefer one or the other, Thuja Green Giant is not fussy, which is another reason for its wide-spread popularity. It will grow in most soils, and the good news is that by digging plenty of organic material into the ground before planting, you can improve any soil type. It improves sandy soil by retaining water, and it increases the drainage and air-penetration in clay soils too. A mulch over the roots – keep it away from the stems and off the foliage – will retain moisture in summer and keep your soil in better condition too, as it slowly rots down into the ground. In zone 5, mulch in spring, once the soil has warmed a little, but in warmer areas it can be done in fall or through winter. Most soils benefit from good soil preparation, which is much more useful in the garden than a ‘green thumb’.
Thuja Green Giant is Versatile
When you consider how adaptable this vigorous plant is, it’s no wonder it is the top-choice year after year. Although it has now been around for decades, there is no sign of it losing its place at the top of the popularity polls. So once you have checked your needs, the chances are good that this plant can satisfy them. With its rapid growth, it won’t be long before that hedge of your dreams is a reality.