Thuja 'Sunny Smaragd'

Conifers somehow seem to have themselves a bad name. That most famous conifer, Leylandii, can cause neighbours to fall out, sap borders of moisture and goodness, cover windows like a curtain, and you’ll certainly never see it used in a garden design! Leylandii IS a garden thug, let’s be honest.

When you first look at this month’s plant, Thuja ‘Sunny Smaragd’, you may indeed have those same fears. However, there’s no need! This plant may look like a Leylandii, but it is definitely not a Leylandii! It’s something really quite different…


The conifer that could make conifers trendy again 

We’ve seen a revival in many plant categories recently, from cacti and succulents to houseplants and grow your own vegetables. However, so far, the renaissance of plants has eluded conifers. Indeed, they still remain popular in quiet pockets of Europe, but haven’t been seen as mainstream or ‘cool’ for a long time.

Can we change that?

Thuja ‘Sunny Smaragd’ has got the look for sure: feathered leaves with a golden tint, handsome shape and stature.. It also has the growing credentials: tough, unfussy about soil.. And, best of all, it behaves itself. Steady growth maxing out at 2 metres… this ain’t no Leylandii, you can be sure of that…!

How was this plant created?

Finding the golden glow of Thuja ‘Sunny Smaragd’ must have been like finding a needle in a haystack! However, thanks to the observant eye of Sebastian at Hoogenraad Plant, it was spotted and developed. One day, Sebastian was wandering a crop of thousands of ‘Smaragd’ green Thuja plants, and noticed one single branch had a golden intensity.

Can you imagine how nerve-wracking it must be to discover the beginnings of a new plant, and then take the risk to produce it? Sebastian had to remove the branch and propagate it, and he also needed to see if it would survive away from the green plant. Golden ‘sports’ on plants can often lack vigour.

Thankfully, Sebastiaan’s risk paid off, and this golden opportunity took root, and grew well. Much better than he ever expected actually. Compared to other golden Thuja, this new plant grew steadily and strongly, with a good rounded shape.

Getting that Thuja from the propagation unit to customers gardens wasn’t an overnight process though, it actually took 7 years of
trails, tests, building and building…

What’s different about this plant?

Sometimes, golden leaved plants can be weaker than their green leaved cousins. This is because there is less chlorophyll. However, green leaved plants can still create golden leaved mutations from time to time. However, they need to be removed to be developed, away from the dominant, and competitive, green parts of the plant.

However, this new plant, by now nicknamed ‘Sunny Smaragd’, was proving to be a strong grower. It had carried on all the great qualities of ‘Smaragd’. It had tough frost resistance, awesome adaptability and a good, manageable shape. The plant was also good at growing in fully lit or semi-shaded positions.

Importantly, ‘Sunny Smaragd’ didn’t need any sunblock! The feathered leaves didn’t suffer sunburn, despite their golden tinge! In fact, the leaves weren’t just golden, but the tips included an extra little sparkle. This warmer overall colour, and more efficient growth, set ‘Sunny Smaragd’ apart from similar golden conifers.

You may also be wondering what ‘smaragd’ means! In Dutch, the word means ‘related to emeralds’, referring to the green of the original plant Thuja ‘Smaragd’..! Now we have sunny emeralds..!

Where can you plant Thuja ‘Sunny Smaragd’?

‘Sunny Smaragd’ works perfectly in the ground as a feature plant, mixed into shrub borders, or in decorative containers on the terrace. The perfect conical shape of the plants is neat and orderly, and that shimmer is a real eye-catcher!

Placing ‘Sunny Smaragd’ either side of a doorway could offer a refreshing alternative to olive trees or bay trees too. The warm hue of ‘Sunny Smaragd’ is also perfect for the ‘Graffiti Garden’ concept, which I’ve covered in recent articles. With so many uses, it’s going to be fun to place this sunny beauty!

Thuja are very hardy and can tolerate a wide range of different soils and conditions, from sun to shade. They withstand pollution, and require no pruning, and demand no maintenance… dare I say, you just ‘plant it and forget it’.. ‘Sunny Smaragd’ is an excellent choice for adding shape and structure to your outdoor space. Once established, plants are extremely drought tolerant and aren’t as thirsty, competitive and thuggish as those devilish Leylandii..

Where can you buy this plant?

Plants are available in garden centres across Europe, or by mail order from here.

How to grow Thuja ‘Sunny Smaragd’:
Location: Borders, patio pots
Soil: Any well-drained soil, drought tolerant when established
Light: Sun or part shade
Hardy: Survives down to -15C! Plant will come back every year.
Care: Nothing to do!
Size: 2m (6”) high x 60cm (24”) in spread
Watch me talk about Thuja ‘Sunny Smaragd’ in this video below:


Plant of the Month is sponsored by Plantipp, a company based in The Netherlands who handle the introduction of new plants into Europe.
Thuja ‘Sunny Smaragd’ was selected by Hoogenraad Plant.


It can actually be quite easy to spot new plants, as nature often does the breeding work for you! Natural variation is referred to as a ‘sport’, just like the golden leaf on the Thuja. Make sure you take time out to get to know the plants in your garden, and if any seem different to the norm, let me know!

See every Plant of the Month here
**Gentle Warning: this post may be sponsored or include affiliate links, however please be assured that any products spoken about have the Plant Geek seal of approval.**
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  • derek myles

    i cannot find any body selling thuja sunny smaragd except crocus, i think a 9cm pot is rather small . would appreciate any suppliers you know of, including in europe if neccessary. thanks in anticipation derek

    January 3, 2021

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