The 40th anniversary of National Tree Planting week stars at the weekend so I thought I would run through a few pointers to help with long term success to establish newly planted trees.

Planting distance

It is very common for trees to be spaced for day one look rather than 50 year look! By planting trees too close together you weaken the strength of trees as they mature because they compete in tandem rather than grow alone. The shapes of their canopies suffer as well as they are drawn up battling each other for light rather than given the space to form a lovely even crown. Most avenue trees are planted at 10 metres apart but after 50 years or so hindsight suggests 12-15 metres apart would make a better show. Another problem from close planting distance is that you have to make a decision later on down the line to remove one to allow progress for the other. Time and money are both wasted in this case!

Tree physiology

When deciding on the tree to plant you have to work with the conditions you have rather than force a tree to grow on land that doesn’t suit it. A good example of this is when faced with a clay soil. Hornbeam, Carpinus betulus, thrives on heavy clay soils whereas Beech, Fagus sylvatica, prefers lighter soil profiles. Both trees are similar and are confused as the same by many but only the Carpinus will romp away on clay once established. Acer griseum is one of the prettiest trees you are every likely to see but plant it in a hard urban area with reflected heat and light and it will surely fail. Plant Acer griseum in a dappled shade woodland environment and it will romp away. You can’t beat Mother Nature on this so always try and match a tree’s physiology with your conditions on site.

Planting depth

Please see previous blog

Ground conditions

Unfortunately tree planting time is generally when the ground is at its wettest and the soil structure most difficult to fashion. Storms Barney and Abigail has saturated the west side of the country and planting into holes that fill up with water is going to end in the failure of the tree. If the weather is against you, delay planting until the conditions are right! Aftercare: Whatever you plant will have to be watered from the following April through to October to get it established. With this in mind concentrate planting in areas per season rather than scattergun across a large area that will be tricky and time consuming to maintain with water in the summer. A watering bag is also a helpful way to ensure trees are getting enough water.

Ask your nursery

We are always on hand to give advice so if you are uncertain on what, how or when to plant feel free to give us a call on 01353 720950 or email [email protected]

There have been many studies about why we like trees so much. Interestingly, when a picture is shown of a mature tree lined suburban street with the trees in place or airbrushed out the preferred choice is invariably the one with the green canopy cover. It is estimated that houses with good tree cover nearby are worth 18% more, ask any estate agent! With leaves in the summer or without leaves in winter, they count just the same.

We all know from our school days how trees release oxygen and lock up carbon and a recent study on the BBC programme ‘Trust me I’m a Doctor’ showed that planting a line of Betula utilis Jacquemontii outside a row of houses on a busy city road made a massive difference to the amount of pollution particulates coming into the houses. They used a simple test of wiping TV screens in houses with no trees, against houses with trees planted between them and the road and the difference in dust build up was amazingly striking. This is of course great news for asthmatics with respiratory problems caused by traffic emissions.

Trees slow down the flow of rainfall hitting the ground to help against soil erosion and their roots similarly lock up the ground to make it stable. They provide important shade to filter out harmful rays that can damage our skin and they both cool our environment on a hot day and insulate our houses on cold ones. Trees slow down the rate of wind, just stand behind a Pinus nigra Austriaca on a breezy day on the coast to find this out, and they create a wealth of food and habitat for wildlife.

But we know all this! The remarkable thing is that in academic studies asking people which of the above are the most important, it comes up with a resounding answer every time: We want large mature trees around us because we like them. Simple as that! Forget the carbon sequestration, the oxygen giving and the respiratory health benefits; it’s their aesthetic beauty that draws us to trees and why we want to be surrounded by them. In a study last year it recognized the weight of new born babies was increased in areas where the mother lived in a green area versus a concrete jungle. It’s this inner contentment and well-being that large mature trees give us that counts the most.

Now that the planting season is in full swing I thought I would re-open the topic of planting depth. Trees are more often than not planted too deeply. In nature a seed lands on the soil from the tree above and germinates with the root going downwards and the shoot going upwards, it’s as simple as that! Roots and shoots are two different mechanisms so it is totally against the rules of nature to heap soil up and over the stem. When this happens the roots are deep within the compacted layer of soil that is least oxygenated and often wet. Tree roots need three vital ingredients to grow and thrive, namely water and oxygen blended in measure and a soil temperature of between 10 and 20 degrees Celsius and these conditions are most likely to occur in the top metre of the soil profile.

A stem baring no roots buried below ground will make the tree unstable in windy conditions with a tendency to rock around in a circle producing a gap between the stem and the existing soil. Imagine blowing a pencil standing on its end off a table, dead easy! Try and do the same with a wine glass and you won’t be able to do it! A well anchored tree is like the wine glass with its roots on the surface spreading out laterally like spokes of a wheel to cover a surface area to hold up its trunk (stem) which in turn supports its crown (cup). Planting a tree deeply can greatly hinder this process.

Quite often root balled trees are lifted with the downward action of the blades heaving soil up and over the stem above ground so the tree is several inches deep before you even get round to planting it. Planting trees a few centimetres proud of the soil line can solve this one. Below ground anchoring systems on top of the roots can also mean your tree is planted deeper that it should be. Digging a hole much deeper than the height of the root system can mean that the roots sink gently into the disturbed ground after planting which is another thing to avoid. Generally speaking it is good to dig a hole twice the width of the root system but the same depth as the root system.

To make this problem totally transparent we offer a chargeable service called the Barcham Line whereby the tree comes with a painted mark at its base. It you can’t see this mark after the tree is planted you know the tree is planted too deep! Trees heave themselves a little bit out of the ground at maturity and you can notice this by seeing their root system diving into the ground from above ground level. You don’t see trees with tubular stems and no basal flare rising from the ground very often!

We are tuned in to symmetry and uniformity for tree line avenues but latest thought suggests this perception would be a good one to break.

I recently took a trip out to Washington and saw there were ranks upon ranks of Elm (Ulmus) planted outside the White House. They looked great and so pleasing to the eye but being all the same means that the genus could be open to a pest or disease problem, in that if one gets infected they will all quickly suffer the same fate. To emphasize this I also saw canker symptoms on about one in thirty of them which is alarming…

Put it this way, I would be very surprised to see the same treescape outside the White House if I go back in 20 years!

Good examples of this have also been seen in the Larch (Larix) plantations in the West Country where thousands of trees have succumbed to Phytophthora ramorum, misleadingly commonly known as Sudden Oak Death. If this disease could express itself it must have been ecstatic when it arrived seeing that it could then predate on a huge number of potential host with no break crop to slow its progress from tree to tree. By mixing the tree population with many different genus you safeguard against one pest or disease wiping through the whole lot years down the line.

Similarly, I have been called out to see several Horse Chestnut avenues (Aesculus) that have been savaged by bleeding canker. With so many new pests and diseases coming into the country via European nurseries it is essential to mix it up. Depending on soil type and aspect I suggest replacing diseased avenues of Chestnuts with a mix of Oak (Quercus robur), Hornbeam (Carpinus betulus) and Lime (Tilia cordata Greenspire) to safeguard against any future calamity that concentrates on a single genus.

In America they thought they had learned their lesson after the Dutch Elm Disease outbreak in the 1960s which savaged their urban tree numbers. Now they have a problem with boring insects that have come across from China and they realise that over 70% of their urban trees are in the Acer genus which is very susceptible to this pest. Disaster, all over again! If you could make sure that what genus you plant accounts for a low percentage of the whole tree population you have insured yourself against problems for the next generation.

I have toured many tree nurseries and I always remember one I visited about 15 years ago in Florida that just grew a single genus of Oak, Quercus virginiana and its cultivars. I thought then this was a dangerous case of ‘eggs all in one basket’. As a tree grower I would now have sleepless nights if I was in this situation! At Barcham we grow 78 different genus across over 450 cultivars across as total of 120,000 large instant impact containerized trees. This is a range I feel more comfortable with!

Most deciduous trees jettison their leaves in autumn as Chlorophyll turns to Xanthophyll, i.e. green to yellow, (coincidentally this won me a session of University Challenge against my wife a couple of weeks ago 5 points to 4!)

But why do trees such as Beech and Hornbeam retain leaves? This is all to do with a physiological condition referred to as ‘juvenility’ where young trees, typically below two metres in height, retain their withered dead leaves to stop predation from deer and rabbits which hate the texture of old dry leaves which protect the young juicy buds beneath. Above this two metre line the trees have no need to protect themselves (not many Giraffes in the UK!), so leaves are jettisoned as normal as the tree loses its juvenility. This is why beech and hornbeam hedges retail their leaves and specimen mature trees jettison them. By routinely cutting these as hedges below 2 metres the plants are kept in their juvenile state, so retaining their dead leaves which get pushed off the tree with emerging new growth in the spring.

A fine example of Charles Darwin’s natural selection evolution theory that also interestingly shows this is Holly, Ilex aquifolium. We all know that holly leaves are prickly but if you look up a maturing tree you will see that the leaves get progressively smoother as the tree has no need to protect itself from grazing animals from about 2 metres upwards. Why bother with expending energy producing spikes if they are not needed?

Deciduous trees are random. You can plant an avenue of trees and they could defoliate in the autumn in different weeks or all at the same time. I’ve found over the years that if you try and second guess nature you will be proved wrong most of the time! Pleached trees on a frame over two metres are a law unto themselves. The pruning triggers all sorts of responses. Even through the tree should be too tall to be in a juvenile state some will still show signs of it while others in the same line do not. This is why you can get a random tree in a pleached row look different to others this time of year. Nothing is necessarily wrong with a tree acting out of sync to its neighbour, it is just wired differently. I can empathize with this, having two teenage daughters!

Some trees have defoliating triggers when planted in leaf. Most deciduous trees planted from August onwards will cast off their leaves earlier than established trees nearby but settle down in the following years. London Plane, Platanus hispanica, hates being planted in the summer and this mostly triggers a complete defoliation within two weeks after planting only to re-flush later on if time allows in the growing season. Otherwise they generally come back good as gold the following spring.

All this is not a precise science, just sit back and enjoy the show! Autumn has got to be one of the most stunning time for trees.

Posted by Mike Glover

Well on this evidence they put a spurt of growth on! I collected over 4,000 acorns from the avenue of Evergreen Oak at Holkham two weeks ago today and after maturing for a week in my office and just as they began to germinate we lined them out in our seedbeds.

I have done the same for the last decade, and the emerging seedlings in the spring were particularly impressive this last summer.

Tree roots grow given three vital ingredients; temperature, water & oxygen. You can aerate ground to promote oxygen within the soil profile and apply water but fixing a higher temperature is out of our control. They put a spurt of growth on for the Autumn to nutrient load ahead of a long winter of dormancy. Recent trials show that a tablespoon of granulated sugar sprinkled on top of a tree this time of year is greatly beneficial with the roots taking up this easily absorbed food supply to give it a boost for the following spring. It costs very little to do, give it a try!

Even during the cold winter months roots will continue to grow, though a lot slower than in the spring and summer. They will extend in soils above 10 degrees Celsius quite comfortably and in this country this means that root growth will carry on year round in all but the harshest winters.

Large and mature trees will be more sedate in their root growth than younger specimens that are eager to satisfy their juvenile vigour.

Barcham has always stocked an unrivalled number of different varieties and genus but this autumn our choice has widened even further! We now stock over 120,000 instant impact container trees across 441 different varieties making us the largest tree grower of our type in Europe. Please see links to our latest new varieties below:

Eucommia ulmoides

Gingko biloba Globosa

Gleditsia triacanthos Draves Street Keeper

Hamamelis intermedia Jelena

Hibiscus syriacus Resi

Prunus Reine Claude d’oullins Greengage

Quercus robur Regal Prince

Quercus palustris ‘Green Pillar’

Sequoiadendron giganteum Glauca

Tilia americana American Sentry

The nursery is looking great this autumn, loads of colour across our broad range. Feel free to call us and make an appointment to tour the nursery with one of our experienced arborists. If you like trees there isn’t a place quite like Barcham!

I bought a Blue Motion VW Golf about 6 years ago on the environmental ticket and feel cheated like everyone else that I have probably been contributing more pollution than I thought. However help is at hand! Recent studies in Japan and America have identified the tree most suited to gobble up diesel particulates from traffic pollution in urban areas and it is beginning to catch on in London.

Magnolia Kobus is a great pollution eater and it so happens to be a very pretty tree as well. As it matures it throws out a good number of pure white flowers in the spring and its lush green foliage turns a clear yellow in the autumn before leaf fall. Magnolia is an ancient genus of tree and this is the parent of a lot of clonal selections. Magnolia kobus isn’t as free flowering as the more commonly planted Magnolia soulangeana but it provides a great public service and can be trusted more than some dodgy car manufacturers.

We grow this tree in large numbers now as a standard tree suited for cities and gardens. So if your home has some planted nearby, you can enjoy some lovely white flower in the spring and be very pleased to have the best pollutant eater on your doorstep!

Contrary to the weather forecast it was a beautiful weekend and there are now the first signs of spectacular autumn colour beginning to show. Every autumn is different which adds to the fun this time of year and even a common native tree can surprise you with its fabulous autumn display. I saw this Prunus avium on the boundary of our local supermarket and it stood out splendidly across the expanse of the car park. The lovely autumn tints of Acer platanoides Pacific Sunset are also coming through and have prompted me to add this clone to our range for sale form September 2016 onwards. It is not only leaf colour that can draw the eye, the fruits on Euodia hupehensis are a stunning red and are particularly vivid against a blue sky.

However, for sustained autumn interest from early September to late November there can surely only be one winner! The Liquidambar styraciflua Worplesdon in my garden gently started turning a few weeks ago and already there are hints of yellow and orange emerging within the dense canopy of leaves. In a months’ time the crown will be a stunning claret and the pretty maple shaped leaves are stubborn to detach themselves from the tree even in a strong autumnal wind. What is more, there never seems to be anything that eats or predates on Liquidambar leaf throughout the growing season so when it does change for its autumn show its leaves are perfect in every way. It certainly is a show stopper with people walking up my road always commenting on it this time of year and asking what it is!

My Liquidambar Worplesdon never fails to deliver but is a medium to large tree at maturity so it is not suited for every garden. The Hamamelis Arnold Promise in my garden is only about 1.5m tall but is routinely smothered by luminescent orange to red leaves which are hard to beat for a small multi stemmed tree. This has been turning for some weeks now as it wakes up for spring early, flowering in February / March. If you see an autumn stunner over the next few weeks and don’t know what it is, feel free to take a phone shot of it and send it through to us so we can get back to you with its identity.

Posted by Mike Glover