In the period leading up to the holidays, almost every garden center sells little pots of a small upright, columnar conifer with “golden” (yellow green) needles as a Christmas plant, often in a suitably colored pot or decorated with ribbons or bells.
It’s Cupressus macrocarpa ‘Goldcrest’, the golden Monterey cypress. It’s also called lemon cypress because of the distinct lemony smell it gives off when you run your fingers through its needles.
It’s a selection of the all-green Monterey cypress (C. macrocarpa), today a very rare conifer in the wild, found naturally only in a few limited localities in California. ‘Goldcrest’ first appeared as a mutation on an all-green Monterey cypress in Treseder Nursery in Cornwall, England back in 1948 and was popularly grown as a garden plant for half a century before Dutch nurseries began mass marketing it as a Christmas plant early in the 21st century.
C. macrocarpa ‘Wilma’, also known as ‘Wilma Goldcrest’, is an even more narrowly columnar golden form that is also widely available. Unlabelled plants could be either cultivar.
Indoors or Out?
Although the golden Monterey cypress is most often sold as a Christmas plant in colder climates, it also makes a good houseplant for use year-round. It can also be grown outdoors in climates with mild winters.
Give it intense light, especially in winter, with 3 or 4 hours of direct sunlight per day and bright light the rest of the time. Otherwise, it will tend to gradually go decline, losing its original yellowish coloration and, eventually, branches. Low light for extended periods will kill it!
It really prefers cool temperatures year-round, in the 55 to 65 °F (13–18˚ C) range at night, especially in winter, and can take down to freezing if necessary, but that’s rarely possibly indoors. Fortunately, it does fairly well at normal indoor temperatures, although it does appreciate it when you lower the thermostat at night. Try to avoid temperatures over 80 °F (27 °C).
Watering is a snap. Just follow the golden rule of watering, that is, watering abundantly enough to moisten the entire root ball, then waiting until the soil is dry to the touch before you water again. How often you have to water can vary enormously according to the size of the plant, the size of the pot and the growing conditions. Don’t ever let it dry out completely, though: if its needles become dry and crunchy, you’ve just lost it: no amount of watering will revive it!
It doesn’t like dry air and that can be a problem in the winter, when the air indoors is often very dry. It may be necessary to increase the atmospheric humidity during the winter months to prevent the needles from drying out. Thus, the use of a humidifier or humidifying tray is highly recommended.
As for fertilizing, this plant is not a heavy feeder and too much nitrogen, especially, can lead to faster but thin growth. Normally, a single spring application of very diluted, all-purpose fertilizer will be enough.
To maintain a compact shape and good coloration, you may need to put your golden Monterey cypress outdoors for the summer. However, don’t expose it too quickly to full sun or it will sunburn. As with any houseplant, you have to gradually acclimatize it to outdoor conditions, starting in the shade, then gradually increasing the light until it can tolerate full sun.
In those climates where it will grow outdoors (zones 8 to 10, possibly 7), golden Monterey cypress prefers full sun or only light shade, plus humid air and evenly moist soil. Careful placing is important: plant it where cold, drying winds can’t reach it. Prolonged temperatures below 20 °F (-7 °C) may damage it to the point where it will never fully recover.
Remember too that it will eventually become huge if you don’t prune it occasionally. And pruning will also be necessary to maintain its columnar shape, as it develops a much more open habit over time. The cultivar ‘Wilma’ is a better choice for the outdoor garden if you’re looking for a long-term narrow habit.
From Little to Big
Typically, the golden Monterey cypress is sold as a small plant 8 to 24 inches (20 to 60 cm) tall or less … but will not remain of this size. It will grow slowly but surely, theoretically reaching in the open 65 feet (20 m) or more in height and up to 12 feet (4 m) wide. That’s far too much for indoors and also too much for many outdoor uses. That’s why you’ll probably have to begin pruning regularly at some point. Do so in spring or summer. You can even prune more than once a year.
Most people will probably prefer to maintain its columnar shape simply by “removing a bit” from the top and sides, but you can also give this plant almost any shape you want. For example, this species is used in bonsai, topiary and—only outdoors, of course—as a hedge.
As with most conifers, don’t prune so hard that you cut into brown, leafless wood, as it doesn’t respond well to harsh pruning and that will leave bare spots.
Also remember to repot indoor specimens every three or four years using ordinary houseplant potting soil. This will help remove contaminated soil (toxic salts tend to build up over time in potting mixes). It also allows the roots more room to spread. If you want to slow down its growth, try pruning the roots in early spring.
You can really only multiply golden Monterey cypress by taking stem cuttings of young branches. Apply a rooting hormone and cover the cuttings with a clear plastic dome or bag until they’ve rooted, then grow them as you would adult plants.
The golden Monterey cypress: more than a superb living Christmas tree, it’s a great plant for growing all year!