Clipping Buxus Sempervirens
Buxus Sempervirens - a growing diary
Following on from our propagating buxus softwood cuttings growing diary. This year we shall be trialing differing clipping / pruning techniques on more mature Buxus Sempervirens plants. The plants we have chosen are all 3 to 4 years old and have been pot grown.
Over the course of the coming year we shall be recording and measuring the growth and any observations we see, so do check back from time to time.
Buxus commonly know as boxwood or box is slow growing and the wood is very hard and has a very fine grain. The wood has been used for cabinet-making and marquetry and even as a substitute for ivory.
Buxus or Box is a popular ornamental plant and widely used for topiary and hedges. The scent is not to everyone's liking, at Hampton Court Palace Queen Anne had box hedging removed because she found the smell offensive.
Box Hill in Surrey is named after its box population which, which has the largest area of native box woodland in England.
Click any of the photographs to see a larger version.
11th March 2012
Our Buxus plants have started to form flower buds (see photo right). How will growth be affected if the flower buds are removed? This is one of the trials we shall undertake.
We selected four similar Buxus Sempervirens plants and plan to clip each of these slightly differently. Apart from clipping, all four plants will otherwise be treated equal i.e., sunlight, water, compost and feed.
Box is a hardy but to get the plants off to a good start we will keep them close to the house and move them inside if there is any chance of frost.
The image (far right) shows a healthy root system of one of the plants.
All flowers have been removed and the leading tips from each branch have been snipped off.
The leading tips from each branch have been snipped off but the flowers have been retained.
We have weighted down the branches on plant 3 to try and create open growth. All flowers have been removed and the leading tips from each branch have been snipped off.
This is the reference plant, it will be allowed to grow naturally and will not be clipped but otherwise treated the same.
1st April 2012 - Preparation
Four Buxus semperverins plants with similar characteristics i.e., shape, size and form were selected and for ease of identification we chose colour coded 30 centimetre "elho" pots, we also labled the pots with a number to further aid identification.
For the compost we want a free draining medium and made a blend consisting of 3 parts John Innes no3, 1 part humus rich compost (home made) and 1 part potting grit. Finally we added a top dressing of potting grit to aid moisture retention and help minimise weeds.
All four plants measure approximately 30 cms (measured from the top of the pot). To plant number 3 (see below) we added non toxic fishing weights suspended with fishing line from its branchs to try and create open growth.
26th April 2012
Decided to add a further two plants to the trial.
Plant 5 (right) has had approx one third of its growth clipped to give a flat hortizontal top.
Plant 6 has been potted on into an 10 litre Air Pot. We have seen Air Pots at many plant nurseries and we are interested to see how plant growth compares using this technology.
Other than the container, plant 6 will be treated exactly the same as plant 1.
Air Pot containers do not have any flat inside surfaces to deflect roots and start a spiralling process. The Air Pot effectively air-prunes the roots.
The claims are that this process causes the plant to send out more roots leading to a dense root system improving oxygenation and nutrient uptake for faster growth rates and healthier plants.
Check back to see how the Air Pot compares in this trial.
15th June 2012
Whilst this trial is limited to six plants we are seeing some interesting differences in growth between the Buxus Sempervirens shrubs. Plant 2 is the tallest whilst plant 3 is the widest and has put on the most new growth. New growth from a larger number (50 plus) of Buxus Sempervirens plants not included in this trial is averaging approximately 7cm.
This year, spring and early summer has had considerable rain fall, we have not needed to water the plants, although we recently gave them a feed by plunging them into a solution of Miricle Grow.
We are worried that the Buxus sempervirens plants might contract Box Blight disease and are regularly looking out for symptons such as browning leaves, black streaks and dieback.
For a larger image click on any of the photos
Back in April we removed all the flowering buds from this plant, thinking that this might encourage more new growth instead of expending energy into flower / seed generation. This does not seem to be the case as plant 2 has a slightly greater rate of growth.
Plant 1 has 8cm of new growth and is now 46cm wide and 36cm tall.
We are allowing plant 2 to develop flower and seed - thinking that this will have some impact on new growth. But this does not seem to be the case as plant 2 is doing slightly better than plant 1.
Plant 2 has 8.5cm of new growth and is now 52cm wide and 46cm tall.
Has had its branchs weigted down in order to try and force wider more open growth which seems to be relatively successful. We shall add more weights to the upper central new growth in the coming days.
This plant has put on the greatest amount of new growth (12cm), it is also the widest (58cm) but this is probably to be expected. The height of the plant is now 44cm.
Plant 4, the reference plant, has put on 10cm of new growth, which is greater that plants 1 and 2. But this was probably to be expected as it hasn't been clipped this year.
Plant 4 is now 50cm wide and 30cm tall.
Was clipped hard and given a flat top. As expected this stunted the plant and it has only 35 - 40cm of new growth. Plant 5 is the most dense compact plant in the trial so far.
Also this plant was not re-potted in spring but left in its original 5 litre pot. Whereas the other 5 plants in this trial were repotted into larger pots; plants 1 to 4 into 12 litre 30 cm wide elho pots and plant 6 into a 10 litre Air-Pot.
Plant 5 is now 25 cm wide and 23 cm tall.
Apart from being potted in a 10 litre Air-Pot this plant has been treated the same as plant 1.
It has 7cms of new growth and is now 37cm wide and 35cm tall.
One observation we have made is that insects (ants) are regularly seen on this pot but not so the others !
In our opinion the the Air-pot is also visually appealing even compared to the other brightly coloured elho pots.
14th July 2012
To provide good drainage we added plenty of grit to the compost when we potted up the plants earlier this year. With the constant rain this summer this has proved to be invaluable as Box doesn't like its roots sitting in water. All six plants have also been sitting on a concrete base which has also helped to disipate the rain water.
Plants 1 to 5 have started to bush up nicely although they haven't put on much more height and width. Saying that we decided to give plants 1, 2 and 3 a second clip, carefully removing one third of the growth on the leading stems and 2 sets of leafs on all other growth.
It will be interesting to compare these three plants with the reference plant (plant 4) as time goes by.
The roots of plant 5 can now be seen protruding from the bottom of its pot so it will be potted on into a 10 litre pot (the same size pot as the other plants in this trial).
As yet we cannot see any obvious difference in growth with the plant in the Air Pot (plant 6).