Lemon Cypress Bonsai Tree (Cupressus Macrocarpa): How to Grow and Plant Care

The lemon cypress is a wonderful cultivar of the Monterey cypress tree. Its typical conical shape, lime green foliage, and citrus scent make it an incredible focal point in any garden, but what can really bring it out, is growing it as a bonsai tree.

It’s probably not the first thing you’d consider making a bonsai tree out of. Perhaps your mind might instantly jump to a pine tree (see also Pine Bonsai Care), or a cherry tree as a more popular option, but it’s exactly the unusual choice that makes it a great challenge.

Interested? Here’s what you need to know.

At a Glance: What You Should Know About Growing a Lemon Cypress as a Bonsai Tree

The lemon cypress is an unconventional choice when growing plants into bonsai (see also Bald Cypress Bonsai), and if you’re after a plant that doesn’t need a huge amount of care, it’s a worthy choice.

Depending on how you shape it, a lemon cypress bonsai may get as tall as 50cm, and about 35cm wide, so you’ll need a big pot. 

If you want the trunk to thicken out on your cypress bonsai, you may need to start off growing it in the ground to begin with, and then pot it up later. 

The lemon cypress is a relatively short-lived type of bonsai tree (see also Hinoki False Cypress for a longer-lived option), usually reaching about 10 years old on average, but this may be much longer depending on the conditions you grow it in.

Can You Grow a Lemon Cypress Bonsai Tree Indoors?

A big misconception for beginners starting out in their bonsai journey is to assume that everything will survive indoors. 

This idea is also spread by a few companies that sell bonsai trees, mislabeling many of them as ‘indoor bonsai’, when really, they should be overwintered inside.

What you have to remember is that most tree species cultivated for bonsai growing still need to be outside in order to survive. 

There haven’t been any genetic changes made to these plants, so their growing requirements need to be similar to their normal, much larger versions.

Most of them require brighter light than indoors will provide, and without any changes in weather, they won’t be able to tell when they should go dormant. Without this rest period, they will die.

One thing that you must know about a lemon cypress tree is that it cannot survive indoors. 

While it can last a year, maybe two inside, it will not thrive, as it needs to be out in the fresh air, as part of your garden’s ecosystem in order to be healthy.

Starting off: Should You Grow a Lemon Cypress from Seed or Cuttings?

While you can grow a lemon cypress into a bonsai from either method, there’s a much easier way.

With lemon cypress trees, and others grown as shrubs, it’s often easier to buy them as young plants, and cultivate them into bonsai trees yourself. 

If you don’t fancy the challenge, you can also get them from bonsai specialist sellers or plant nurseries.

How to Make Sure Your Lemon Cypress Bonsai Tree Thrives

Sunlight and Position

Lemon cypress bonsai trees require as much sunlight as you can give them, in a warm, sheltered area. They won’t thrive in dappled shade, so make sure you have a place in mind before you get your lemon cypress bonsai.

In winter, you may need to bring them indoors, or provide them with some protection from freezing temperatures, as the lemon cypress bonsai won’t tolerate frost.

If you decide to overwinter your lemon cypress bonsai indoors, make sure it’s in the brightest place possible, but away from any sources of heat or drafts. 

You’ll need to provide it with cooler temperatures in the winter than you would in summer, in order to signal the dormancy period, to give your bonsai a rest period. This should be around 60°F indoors.

When to Water a Lemon Cypress Bonsai

Lemon cypress bonsai trees are quite demanding when it comes to watering. 

You’ll need to give the plant a good drink whenever the compost feels dry, as letting the plant dry out will render the needles brown and dry. They’ll also lose their signature scent, too.

Should You Feed a Lemon Cypress Bonsai?

A lemon cypress bonsai will benefit from one feed in early spring, to help bolster the plant’s growth. A slow-release, granular fertilizer is best, but make sure it is a balanced formula, such as 20-20-20.

Apart from this, you can save your fertilizer for more nutrient-hungry plants.

How to Repot a Lemon Cypress Bonsai

Only repot your lemon cypress bonsai during the height of summer, where it should be at its healthiest. 

For a younger lemon cypress, they’ll need repotting every two years or so. These beautiful trees produce new roots quickly, but they aren’t tough to prune. 

For much larger lemon cypress trees, you can wait between three and five years, checking for any enterprising roots coming out of the drainage hole every few months.

Remove most of the old soil, leaving some around the roots, and fill the container with fresh, well-draining soil.

Trim back around a third of the roots, taking out any dead or diseased material. Give your lemon cypress bonsai a good drink after you’ve repotted it.

How to Prune a Lemon Cypress Bonsai Tree

The right time to prune your lemon cypress bonsai is either in autumn, or the first few weeks of spring. This is when the tree is still active, but it’s putting out less growth than it would during the summer.

When new growth starts to split into smaller stems or leaves, you can then cut it back to a desired shape or length. 

Avoid the temptation of just snipping off errant leaves or stems before this happens, otherwise anything you prune could die back in autumn.

Problems to Watch Out For

If you give your lemon cypress bonsai the right conditions, it will withstand most problems. However, that doesn’t mean it’s immune to everything. 

Here are some of the most common problems that can weaken your bonsai.

Yellow Leaves

If the leaves on your lemon cypress bonsai start to yellow, this can be a sign of overwatering, or a lack of the right nutrients.

However, if you’ve chosen the ‘Goldcrest’ cultivar, as you might guess, yellowing foliage is normal, and it’s a feature of the plant. As long as the leaves feel healthy to the touch, the plant is fine.

Leaves With No Color

If the leaves on your lemon cypress bonsai tree start losing their color, this is the plant’s way of telling you it’s not getting enough sunlight. Move it to a brighter position, and you should see the color return.

Why is my Lemon Cypress Not Growing?

In spring and summer, if you notice that your lemon cypress bonsai isn’t growing at all, this can suggest that the plant needs a bigger pot. If it gets root bound for too long, the growth will slow, and stop altogether.

To confirm it, gently ease the lemon cypress out of its pot. If you see masses of roots that have grown to the exact shape of the pot, you need to prune them back and repot it.

Lemon Cypress Turning Black

If you spot your lemon cypress bonsai tree turning black on both the leaves and the foliage, you may have an aphid infestation. 

Aphids leave a sticky substance on the plant called honeydew, and this stuff is the perfect breeding ground for mold, which is responsible for the sooty appearance.

This is just one possibility. If you can see aphids, you’ll need to treat both the pests and the disease. For the pests, use a pesticide, or introduce more flowers into your garden, attracting aphid predators such as ladybugs.

For the disease, use a cotton swab dipped in rubbing alcohol, treating the affected areas.

Final Thoughts

The lemon cypress makes a great bonsai for its beautiful lime foliage, citrus scent, robust trunk and easy to care for nature. It’s bound to make a statement in any garden. 

It works well as an experiment you’ll learn from in caring for other bonsai trees, if nothing else.

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