by Ken Lain, the mountain gardener
The idea of using living trees over fresh-cut trees to decorate for the holidays has increased in popularity. A quarter of my local Christmas tree sales are for living trees that will be indoors during the holiday season, then planted outdoors in January.
Because of their waxy needles and high internal pitch, most conifers need surprisingly little water. This is true for the high country natives like pine, cypress, cedar, and juniper. Once these trees reach their mature sizes they thrive in our arid climate, dry soil, and extreme mountain temperatures.
Evergreens do not like to sit in wet soggy soils; the trees’ internal metabolisms will slow to an almost stasis-like state. When planted in soil that drains properly, new root hairs and next spring’s candle buds will form successfully. That is why digging the right size planting hole and adding the correct soil amendments are critical to a successful planting.
Here are seven steps to plant an evergreen tree successfully, no matter the season.
#1 Bowl Shape – The bowl-shaped hole should be the same depth as the root ball, but three times as wide. Plants do not need a deep hole; they thrive when able to stretch out just under the soil’s surface in search of food and water. This is why a bowl-shaped hole promotes the best root development. Rid the hole of rocks and pieces of debris larger than a golf ball.
#2 Improve Soil – Improve the planting soil by amending with composted mulch. Good mulch will keep clay soils loose and aerated, and in loose granite will retain water up around the root ball.
The amount of mulch per plant should be equal to the size of the root ball. That is the quantity of mulch you will need to blend into the native soil that is used to fill in around each plant.
#3 Plant on a Mound – Evergreen trees are so sensitive to soggy soil that it is recommended they be planted on a slight mound. Whatever you do, don’t bury the plant; keep the trunk out of the soil. The top of the root ball you see in the grower’s pot should be able to see sunlight once planted.
#4 Feed for a Strong Start – Evergreens need the right plant food for a healthy start. Use my specially blended “All-Purpose Plant Food” 7- 4- 4, specifically designed for mountain plants. Just sprinkle the granules on top of the root ball and water in well. The slow-release nutrients promote a deep green color, while encouraging thicker root growth with each watering.
#5 Promote Deep Roots – Promote deeper roots with ‘Root & Grow’. Add this liquid rooting hormone to the water used to saturate the root ball. It forces new root hairs to grow, and more roots mean a more vigorous plant. Use this root tonic once per month until new candle growth emerges in spring.
#6 Insulate – Top-dress the planting area with a 3-inch layer of shredded cedar bark. This layer of nature’s insulation retains the soil’s moisture, keeps out weeds, and protects roots from extreme temperature swings. It is like laying a thick blanket over the roots before they are cold and shivering.
#7 Irrigate – Keep the tree moist, but allow it to dry between waterings. Give it a thorough soak twice a month through March. Once it begins to develop new growth bump its watering schedule up to twice a week during the first growing season, then once a week thereafter.
For exact planting details that include drawings and measurements, ask for my “Guide to Mile High Planting” the next time you visit the garden center. You might also like the useful companion guide “Mile High Watering”.
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Evergreen of the week is the Single Blue Pinyon – This evergreen, with a starring role in the mountains of Arizona, is gaining nationwide popularity. Although a local rustic variety, its tidy appearance, and unusual blue color give it a bold appearance. It blends well in dry mountain landscapes, with modern settings, and in Mediterranean-style gardens. However, this tree is gaining popularity at farmers’ markets for its pine nuts. Even young trees produce pine cones with melt-in-your-mouth buttery nuts. Let it grow wild to 10’ or, for that groomed Christmas tree shape, prune it right after its spring growth.
Until next week, you’ll find me in the evergreens here at the garden center.