Also commonly referred to as the Goldcrest Monterey Cypress, Cupressus macrocarpa ‘Goldcrest’ (also known as Hesperocyparis macrocarpa) is a Monterey cypress cultivar with upward-growing branches. The unique yellow-green color of the lemon cypress can play off darker greens of other conifers, while texture can be experimented with by placing the shrub next to boulders and fencing.
Light
The tree requires a good amount of light. Outdoors, it should be planted in full sun to partial shade. Indoors, it needs five to six hours of indirect sunlight or morning sun. The hot direct afternoon sun in a west-facing window can be detrimental to the vibrant foliage.
Soil
Planting this tree in soil that is too rich invites trouble. The lemon cypress is adapted to grow in poor, sandy, well-draining soils that are low in organics and not very fertile. This infertile soil allows the slow-growing tree to pace its development to match its height with its roots, helping to ensure that winds do not blow the thin and narrow plant over.
Water
As an outdoor shrub or tree, once established, the lemon cypress needs little supplemental watering. To allow the plant to establish itself, water once a week during the first season. If kept as a houseplant, give it a thorough deep watering weekly, ensuring the soil is never too dry.
Temperature and Humidity
A lemon cypress prefers cool, moist climates. Temperatures above 80 degrees F in dry areas will tax the plant, while temperatures lower than 20 degrees F may cause tree damage or death. When used as a houseplant, the lemon cypress needs to be kept in a place that has sufficient humidity.
Fertilizer
Fertilizing this shrub is not suggested. The lemon cypress is adapted to thrive in poor, infertile soil conditions. Rich soils will cause quick, uneven growth and could result in the tree being unstable.
Other Varieties of Monterey Cypress
In addition to the straight species. Cupressus macrocarpa. a few cultivars of Monterey cypress have been bred:
C. macrocarpa ‘Goldcrest Wilma’, a slow-growing dwarf cultivar, 6 to 8 ft. tall, and 1 to 2 ft. wide, with fragrant, golden yellow needlesC. macrocarpa ‘Golden Pillar’, with golden yellow needles when grown a sunny location, and a mature size of 20 ft. tall and 4 ft. wideC. macrocarpa ‘Citriodora’, a slow-growing cultivar that can reach 15 to 30 ft. in height. New growth is bright yellow and turns deep green in the first year.
Pruning
The tree looks impressive in its natural, untrimmed, slow-growing upright shape. The only regular pruning maintenance required is when the lemon cypress is used as a hedge or as a bonsai or topiary. In these cases, it needs to be done carefully and in a timely fashion. This shrub, like most conifers, does not take well to hard pruning.
Propagating
The best time for propagating lemon cypress from cuttings is in the winter. Here’s how it’s done:
Growing from Seeds
Most Monterey cypress are cultivars and propagating them from seed does not produce a plant with the same features as the parent, therefore propagation from seed is not recommended.
Potting and Repotting
Excellent drainage is crucial for lemon cypress so make sure the pot you use has large drain holes. Terracotta pots are ideal because they let air get to the roots but the pots also dry out faster so adjust the watering frequency accordingly. If keeping the lemon cypress in a container, it should be repotted once every three to four years. Move it to a larger pot at least one inch wider than the old pot and backfill with fresh potting mix. Prune the roots conservatively to keep growth in check while repotting.
Overwintering
Even when grown in a temperature range where it can be grown outdoors, cold winter winds burn the needles so the tree needs some protection. Below USDA zone 7, lemon cypress is best grown in a container and brought indoors during the winter. Keeping the tree moist during the winter is vital and will be most difficult when a heater is being run or windows are shut. Misting or a humidifier might be needed to help supplement the ambient room humidity.
Common Pests and Plant Diseases
Monterey cypress is prone to attacks by aphids, mealybugs, caterpillars, and scale insects. These usually don’t affect the overall health of the tree and can be controlled with insecticidal soap. A more serious problem is coryneum canker, a fungus that can kill the tree. To keep it under control, remove infected branches promptly and dispose of them in the trash.
Common Problems
After pruning a potted lemon cyprus, you might notice that the tips of the pruned branches turn brown. That is part of the natural process and the brown spots should be disguised in due time by new bushy growth.
