Growing Tree Ferns

Everything you need to know about growing tree ferns

Let’s establish right from the very beginning of this blog post that I am no tree fern expert. We live in London and had never even had any outdoor space until moving into this house. I only planted my first garden plant at the end of last summer. But, I have fallen hook line and sinker in love with creating our little yarden – the planning, the design and now the planting and even the maintaining of it (you have that in writing now so no whinging about weeding from now on).

I really have loved the entire process. I only wish I’d discovered my love of gardening sooner as I now have a great deal of learning and catching up to do. I’m kind of picking it up as I go along, I don’t always get it right but I think gardening is a little bit like that, you have your success stories, like the broad beans that I just threw into some soil, ignored them for a few weeks and voila we have a bean stalk that even Jack would be proud of.

On the flip side though, you also have your absolute howlers, like the supposedly indestructible ivy that continuously looses the will to live within a week of moving in – EVERY BLUMMIN’ TIME. There are so many variables and components involved. I suppose it’s a bit like baking a cake, you might follow the recipe to the letter but you wont get it right every time.

“We used our tree ferns to zone the different spaces in our garden.”

One of our biggest success stories has been our tree ferns. Affectionately referred to as the twins, Arnold and Danny. They are one of the main points of interest in the middle of our garden. They really give it the wow factor. We realised more than ever this year when we trimmed off all of the leaves, just how much they were missed for the few weeks that it took for them to grow back. The garden almost looked smaller as we immediately lost that sense of depth in not having something to separate and zone the space.

“Compared to other large tree’s, tree ferns are great value for money.”

Larger plants and trees are an expensive investment so you need to make sure you’ve done your research and that you know how to plant and care for them properly as you want them to have the best chance to really thrive and grow. I did my research, and soon realised that there isn’t actually a lot of information about looking after tree ferns, and the information that I did find was quite contradictory. Like I said, I am no expert but this is what I’ve learned whilst planting and growing ours over the last 12 months.

Why we chose tree ferns

Description from the Royal Horticultural Society – ‘Tree ferns are slow-growing architectural plants with spreading fronds above a thick trunk. They make striking plants for a sheltered, shady garden.’

Sign me up I said. We’d originally considered olive trees but after doing our research we were worried that the London clay in our soil would not be the ideal conditions for them as they don’t like to sit in moisture for too long and actually, with all of the architectural grasses and ferns filling up our mood boards they didn’t quite fit in from a design perspective.

There was one problem though, the spot in the garden that we had in mind for the tree ferns was not a shady one. The ferns would actually be really exposed in the centre of the space. I contacted the Lindon from the tree fern nursery who has been keeping tree ferns for over twenty years and he seemed confident that if we kept them watered they would be absolutely fine.

We piled into the car and drove over to Leahurst Nurseries in North London “just to take a look” and before we knew it, we’d crammed a 4 and a 2 ft tree fern into the car to come and live with us. We had fallen in love with them hard – what can I say, when you know, you know.

The nursery was the most amazing place, there were so many tree ferns to choose from, and in comparison to other trees, they were very reasonably priced at £20 per foot of tree.

One of the other main selling points for the tree ferns was that they only grow up to 1 inch per year which is perfect for a small ‘yarden’ like ours.

A guide to planting

We made sure that when we left the tree fern nursery we had full instructions on the best way to plant them. This is the benefit of buying them from an expert as oppose to a garden centre.

Until you get around to planting them, ensure that you keep the trunk and the root ball nice and soaked in water. The great thing about tree ferns is you CANNOT overwater them, so don’t be shy and they won’t go dry. Ooooh, I like that…

You will need to dig a hole at least 10 cm’s deep. We dug down into about 2 feet of rubble using a jack hammer, which was actually quite useful as we were then able to use the broken up rubble in the base of the planting bed for drainage.

Add your layer of organic matter. You can use bark or mulch. We used ‘Gro-Sure’s Smart Ground Cover 100% Natural Mulch‘.

Thoroughly soak the mulch and the root ball of the tree ferns with a hose pipe or watering can.

Hammer in your wooden stakes into the location where you want your tree ferns to go. Place the tree fern butted up nice and tight next to the wooden stake and pack in firmly with mulch, bark and soil. We used 3 bags of retained soil that we dug out of the hole at the start. If you’re planning on doing this, make sure that it doesn’t contain any rubble or clay. We gave the soil a good sieve just to make sure.

Cover with a layer of top soil.

We kept the stakes in until the tree ferns made roots, which only took a couple of days but we waited a week just to make sure. Lindon, from the tree fern nursery said that they grip onto their surroundings really quickly. We gave the trunks a firm push just to be absolutely certain that they had taken root. It may take a bit longer for taller trees so you may need to play it by ear but you’ll be able to tell when they feel nice and sturdy, but if it still feels wobbly give it a bit longer.

Here’s what we used:

• 6 large bags of mulch
• 2 large bags of bark
• 3 bags of retained soil
• 2 large bags of top soil

Water the crown of the fern (which is the centre of the plant – the point where the fronds grow) and the trunk daily for six months after planting, and then keep it moist after that, particularly in unsheltered, sunny spots like ours. Never allow them to dry out. I water mine daily from early spring until late summer unless it has rained that day. Remember, you cannot over water them so it wont hurt to give them some more if you’re ever unsure – another rhyme, I’m on fire in this blog post.

Avoid using plant food for the first 12 months. After the first year of planting, apply a liquid feed once a month, from mid-spring to mid-summer, when the plant is in growth.

BIG TIP. In the first summer of having the tree ferns we noticed that the the leaves were looking a bit scorched. We would water the leaves daily to try and stop this from happening but this spring the penny finally dropped. I learned that spraying or misting house plants that sit in the window or in direct sunlight is not a good idea in hot weather as the leaves will get scorched.

This year, when our new fronds eventually unfurled I decided to no longer spray the leaves and see what happened. I literally haven’t sprayed them once, I keep the watering to the crown, trunk and base only, and guess what? The leaves have never looked as green and lush – so there you go, if you are thinking of planting your tree ferns in a sunny spot you can have that tip for free.

Another thing that I’ve noticed is that tree ferns do not like their leaves being knocked about in the wind. We’ve placed ours next to the pergola so it’s been pretty unavoidable for them to suffer the odd blustery day and get a bit damaged by the posts as a result – especially since the leaf span is much wider this year. It’s just something to consider when you’re planning you’re garden. You might want to allow them a little bit more space where possible so that this doesn’t happen.

“When do I cut off the fronds for the winter?”

Ah, if only I had a pound for every time someone asked me this question. I’ve done quite a bit of research and the truth is that I still don’t really know the answer. There is a lot of conflicting information and opinion on this, which I guess is your answer – it doesn’t really matter. My advise would be to use common sense – if the leaves are looking tatty and the trees are in an exposed spot, where they could suffer from frost or wind damage, then take them off when you wrap the trees up for winter in late October.

Similarly, you should take them off if you live in an area that reaches low temperatures in the winter. We live in East London so the climate is pretty mild around here. We haven’t even had snow for the last couple of years so I was more than happy to leave the leaves on until the spring.

Another thing I’ve realised, is that online garden centres often transport the trees all year round with the leaves completely removed in order to make them easier to deliver. New fronds usually appear in early spring time, around March/April, so if your tree fern arrives in late September, then you might not get any new fronds until the following spring, which again kind of proves that no matter when you give your trees the chop, you will still get your new growth in the spring – so don’t panic.

This is what we did

We kept the leaves on throughout the winter as I couldn’t bear to look out onto a bald tree for five months of the year. We eventually gave our tree ferns the chop on the 15th April when we could see the new fronds peeking through the middle of the crown, to give them more room to grow. The minute the old leaves were gone, the new ones literally unfurled about an inch in front of our eyes. It was a really sunny day so maybe that gave them a little boost.

All in all, it took about 4-6 weeks for the fronds to fully unfurl. By about week two I was regretting the decision to cut them all off as I really missed the impact that the bushy leaves create in our garden but, once the leaves fully unfurled we knew we’d made the right decision. They were bushy and lush green – they looked the best that they had ever looked. Even better than the day we brought them home from the nursery.

So would I chop them all off again? Absolutely I would. It was worth looking out at bald stumps in the end, even if my garden Instagram photo’s were put on hold for a few weeks – I know, the very idea of it.

Top tip – this is IMPORTANT. Cut the old leaves one inch from the crown using secateurs. This is how the tree trunk continues to grow – if you continuously cut the fonds right back to the crown the tree will eventually die.

The leaves will stand proud at first but don’t panic, they do drop and become much more feathery once they’ve had some heavy rain on them to weigh them down and, the wind will fluff them up a bit over time.

It’s a wrap

Finally, lets wrap up this blog post by tucking up our tree ferns for the winter. It’s such a lovely ritual in the Autumn, to say goodbye to the summer and hello to those cosy evenings drawing in, and the changes in the season.

This is probably the most high maintenance part of owning tree ferns, but don’t let it put you off as honestly, it doesn’t take long and it’ll give your ferns the best chance of surviving the winter months. I did have a few people on Instagram slip into my DM’s accusing me of being “extra” and claiming that they don’t bother doing this at all, and, that their trees have been absolutely fine. I personally will continue to do this though as you just never know when a cold snap might come out of nowhere and freeze up your fronds – shudder.

All you will need is:

• Chicken wire (enough to wrap around the entire trunk with an extra one inch around it’s diameter)
• Barley Straw
• Hey bedding
• Wire cutters or pliers

We used 2 bags of hay bedding and 2 bags of barley straw to wrap our two trees.

First, wrap the chicken wire around the trunk and cut it to size using your wire cutters or pliers. For larger trees, you might need to add two rows of wire; one on top of the other. Use the loose ends of the wire grids to make hooks, and hook them onto the other end of the cylinder. Make sure there is at least one inch spare around the entire trunk, as this is the empty space that you will be packing with straw to keep the trunk protected from the elements.

Using a combination of straw and hey, pack around the trunk so that it’s nice and compact – this bit does take a bit of time. You can use a broom handle to keep pushing it all down to the bottom.

Once you’ve finished the trunk, use the softer hey to pack into the crown at the top of the trunk – this bit is really important as it is the heart of the tree so you want to keep it protected. Even if you don’t do anything else, do this!

We unwrapped them again on 21st March for the spring with a little bit of hay put aside just incase any April cold snaps appeared out of nowhere. They didn’t, but it’s good to be prepared just in case.

And that’s all there is to it, she says 168494 words later. I hope you found it useful. I certainly could have done with a blog post like this to answer some of the questions that I had about their upkeep over the last 12 months – which is really my main reason for writing it.

Good luck and if you do plant any tree ferns in your garden I’d love for you to tag me on Instagram @the_wooden_hill or let me know in the comments below.

O-fern and out.

For more houseplant care tips and advice on how to introduce biophilic design principles into your home or workspace, you can read Marianna’s new book ‘At Home with Nature‘.