Monday, 9 October 2017

Be brave when you prune

I mangle my holly and contort my hazel
Devastation not yet complete
Suppose a young holly increased by 50% year. Not a foolish assumption if it had sufficient light, water and nutrients. You might come to the conclusion that your tiny plant was slow growing especially if as in our new garden fifteen years ago the rabbits found young hollies to be tasty morsels. We had several false starts!
After sixteen years this same mathematics leads to a new situation where your shrubs and trees start to take over and submerge less determined neighbours.
It is normal to control this process with endless variations of regular pruning. Where gardeners have done nothing for a decade or so of almost exponential woody intrusion they might have a problem.  When I retired from teaching 25 years ago I had clients who employed me to provide a solution.
Answers might include plant removal to give others space to grow or very severe pruning. Some shrubs actually rejuvenate if cut completely back to the ground. 
I remember in my former garden I completely redesigned a complete section of my garden to exploit a few lovely large specimens.


I have rather neglected my seven now rather large hollies. I have enjoyed their progression but now find that rather than contributing to the structure and beauty of my garden they now need take on a modified role.
My picture post shows my three hours of fun on the first two. You might not approve!
I have to tell you that when I prune large challenging plants I go into a kind of fury and prunings fly everywhere. Very large pieces are quickly detached. There is no ponderous musing or starting with small shoots that later need shortening!  Two days later I have had aches all over as my body accommodates to unusual strife. 
I don’t want to say that you must turn into a whirling dervish to prune more to make the point that pruning should not be thought to be a delicate matter that a gardener need fear. (Perhaps also to prove to myself that an old man can still hack it)

I 'trunk' two old hollies
Some shrubs when cut hard back into old wood look very horrible - especially old conifers such as cypresses. The answer is often to go the whole hog and make them a tree!

I had to cut my way in to the central trunk starting with secateurs and as I progressed taking out bigger pieces with loppers
I found under the external surface more berries than I had expected

At this point you start lopping away as you work up and down the trunk. The only skill is judgment of how far to go
A saw is needed to cleanly remove 'snags'
Neither of the above cuts are quite close enough but it is important to leave the clear shoulder on the trunk. Four snags have yet to be cut.


That's better

I have judged to leave the remaining branches and completely take out a metre of top

Trunk not yet completely cleaned
The top needs to be cleaned up using secateurs to create a pleasing shape

It takes a while to get used to the new look of the garden - but so much better.
I have gained an extra four square metres of space for underplanting. New growth on the holly will soon fill out a more pleasing head. Note no ridiculous and harmful tree paint has been used.
The second holly by my garden entrance was a similar problem complicated by having made several secondary trunks right from the ground. It was best to trunk this too. It is a variegated hedgehog holly with several extra spines.


Rosa 'Nevada' and The Bishop of Llandaff were having a bad time

This one also lost more than a metre of top

This was the prunings from just the first holly
Some notes for when I prune the rest of my holly

I intend to reduce this one but maintain foliage right to the ground
I might even use my hedge trimmer


These reverted shoots need removing
Skirt needs lifting
This one needs its ground level dimensions reduced by 50%, its top narrowed and stay clothed right to the ground.

See hazel's bones
The corkscrew hazel Corylus avellana contorta dangles beautiful soft yellow flowers in late Winter and in most gardens is an ugly monster!
The reason is that the beautifully sculptured curves of the branches naturally grow too closely together and make a very dense canopy. Worse just about every plant you buy grows vigorous suckers that grow as straight rods from the ground. Many gardeners are fearful of pruning and after a year or two have nothing better than excellent beanpoles for their runner beans.
I have been promising myself to thin out my plant this Winter when the branches were more visible. I was in the mood with the holly and took a further five minutes to remove 50% of the branches and in this case barely reduce overall dimensions

Crowded between the pittosporum and cut leaf acer it is also far too dense
It needs to be light and airy
Links to further reading
wrote about holly
I am anxious to tell gardeners to prune out reverted growth
I also natter about gardeners' lack of confidence when pruning trees
My original pruning class
I detest tree paint



Thursday, 28 September 2017

RHS honey fungus hunt

Armillaria, honey fungus or bootlace fungus - they all mean the same, but very importantly come in different kinds

Armillari mellea
My previous post about this much feared disease suggested that finding it in your garden is not the disaster it is cracked up to be.
When I received an email from the RHS announcing their fungus hunt I took the opportunity to wing back a link to my my rather complacent post.
The very next day I received a long reply from RHS researcher Jassy Drakulic. The kind of things that I was saying were exactly what she would like to know. The RHS are fully aware about all the damage that the bootlace fungus can do. Members send them their problems! Members don’t usually bother to tell them when no harm has been done. They are now inviting the general public to report their experiences.

The RHS would like to know
Have you honey fungus in your garden?
If so what damage has it done and to what?
Equally important what plants remain healthy?
Have you found bootlaces and yet no or little damage at all?
Do you have pictures of armillaria mushrooms - they need to identify which kind you have got.
Have you historic experience of honey fungus in your garden or elsewhere?
Do you have strange mushrooms growing on living or dead trees or in the ground that you suspect to be honey fungus?

Tell the RHS your story. The link at the bottom will take you to the details of their internet hunt. They ask for quite some detail but don’t be put off and if you provide very little information it is better than none. I wasted ten minutes trying to find the link to find the right form! Silly me - just press the link  ‘complete survey’ under the picture of the mushrooms!
Although Jassy might contact you about further details please don’t expect any identification service. You need to be a RHS member and go down a different route for actual advice!

Why don’t RHS get a complete picture?
Apart for the obvious that people only send in their problems there might be several reasons

1. Gardeners fail to recognise a plant death is due to honey fungus
2. Certain plant deaths get noticed! A dead tree or a hole in a hedge is pretty obvious and might lead to disproportionate  reporting.
3. The obverse of point 2 is gardeners do not expect bulbs or herbaceous plants to be killed - but they can be.
What on earth is happening to my evening primrose?
4. Some plants are disproportionately reported when the real cause of death is susceptibility to such as drought, poor drainage or winter cold  and the bootlaces join the party later

Don’t panic
My opinion is still that honey fungus is excessively feared as the kiss of death to a garden and that gardeners go to exorbitant lengths when evidence of bootlaces are found.
Jassy took me to task with some of the details in my previous post and I reproduce part of her e-mail to me here.

Hi Roger,

Thank you for your e-mail! I’m trying to gather as much information about how Honey Fungus affects gardeners as I can and case studies like those you’ve described are really valuable to me to get a better perspective of the reality of the disease impact and how people interpret the science based on what information is out there.

From the look of those mushrooms they are sulfur tuft (Hypholoma fasciculare) not HF as the spores are dark not pale and there is no annulus. The bootlaces are HF however, and given the abundance of them along with how few plant deaths your garden has had, it is likely to be colonised by Armillaria gallica. This HF species is not a true pathogen at all but only an opportunist that can kill once its host plant is weakened in some other way (pests, mechanical damage, drought - rather than waterlogging).

The point that is made in the blog post is the very reason for this year’s Honey Fungus Hunt! Our last survey (2004-7) was based on samples received at the RHS, which itself limited the dataset to only times when host plants had died, so understandably we got lots of incidences of the most pathogenic species in gardens – A. mellea. By asking the public to record any mushrooms they see, which plants they’re found with and how healthy those plants are I can get a better picture of how often HF occurs without causing plant death as well as gathering any historical information about HF in their gardens that they wish to share. (https://www.rhs.org.uk/honey-fungus-hunt).
The survey will also help gardeners ID HF for themselves better – with such resources available the person ID’ing your mushrooms would have been able to tell that it wasn’t right because of the spore colour, for instance (https://www.rhs.org.uk/advice/profile?PID=1017).

The two links in the email are very useful

Recognition of bootlaces
Bootlaces - not roots
Bootlace - and roots
Bootlace
Jassy tells me that if in doubt between roots and bootlaces  if you laterally tear a suspected bootlace you get a very strong fungus smell


Not sure about this. The white specks are fungus mycelium - looks like mycorrhiza?
I suggested in my previous post that it is something of a lottery whether your honey fungus is a curse or a damp squib. I noted that if you hit the jackpot and had a susceptible plant that is old and growing in predisposing conditions you might be in trouble. I today add a fourth variable to consider - whether you have a benign or aggressive species or strain of the fungus.
Jassy in her e-mail made the fascinating point that a less aggressive species such as Armillaria gallica might be antagonistic to the more serious effects of the feared Armillaria mellea.

Some more examples of my own confusion

1. My Spartium junceum, Spanish broom, was checked and lost its youthful vigour after record cold Winter 2010. It's never been the same. It lost its main frame trunk but a strong shoot from the ground took over and made a 'passable plant'. It is in the area that I previously reported honey fungus and for this post I recently scrabbled around.


Stump several years dead and still surviving trunk 
Today, October 2017. The top is still nice - and I hope the plant is recovering


What have I got?


Former misidentification of honey fungus - picture previously  taken near my spartium
2015 picture of original tree stump two metres away from spartium
2. When walking through a near village I spotted thirty or so fungal fructifications emerging from a manicured lawn under a dozen or so healthy mature specimen birches. My own identification skills are such as that I would not be sure of a common mushroom. I did not have opportunity to examine more closely. Most such fungi are completely harmless. Do not fear to submit to the survey if you are not sure.

Perhaps someone can tell me. I dare not go closer

3. In my previous honey fungus post I pictured a somewhat distressed lilac growing in my 'infected 'zone'. It ticked the right boxes. When we moved in fifteen years ago we had pruned it down from an overgrown thicket which had had several trunks.We had also chopped down half dozen old Leylands and being me I had left stumps in the ground! The site is very dry in Summer. As I say all the right boxes, hard pruning, potential source of infection, summer drought, old plant and a susceptible species (nineteenth on the previous RHS survey).
Worse I have allowed my ivy to grow over it - always a symptom (and cause) of a weak growing plant. For ten years now Brenda has told me its on the way out and I should remove it. Every year it flowers magnificently.


From my post three years ago
I really must prune out some ivy
A young sucker is ready to replace the old lilac
Links
I was very cavalier about leaving tree stumps in the ground in this old post. The only amendment I would make to my advice is that I failed to emphasise to cut your tree trunk close to the ground. This is not relevant to honey fungus - or is it with a greater dying food source? - it is forgetting it is there and tripping over!

My original post on honey fungus




Thursday, 21 September 2017

Are fertilisers a good thing?

My giant borders neither need or receive fertiliser. Were they to need extra nutrients I would have no hesitation to apply a top dressing of general fertiliser

I am tempted to say  fertilisers are ’the best thing since sliced bread’ but then I reflect that much bread today is not very nutritious. I might even say ‘junk food’. But then many gardeners think that fertiliser is junk food and sometimes it can be! Bonemeal anyone?

I have written about fertilisers many times before. I don’t like to repeat myself - although regular readers might not think so. I cannot completely avoid it when new readers have not yet heard  my ramblings. I have passed on most of what I know and worse, have used up my best ‘jokes’ and stories. Today I will limit my attempts to guide you to the more practical aspects of fertiliser use in the links below. (I don’t want to lose you by sending you into the ether too early) There are a lot of links today which I hope will serve as a reference. For example, I explain that when I talk about fertilisers I mean ‘concentrated sources of nutrient’ and not bulky manure. Bonemeal does not qualify as either.

Not only do my borders usually not receive fertiliser I do not import bulky manure  

Growmore is a far superior general fertiliser to bonemeal
The thrust of my item today is to question how much gardeners need to use fertiliser. Scientist Peter Williams has no doubt of their value and neither do I. If your plants have insufficient nutrients they will fail to achieve their genetic potential. This might include anything from size, speed of development, health and disease resistance, flower and fruit size, colour, absence of deficiencies and plenty of flavour. Neither of us have any inhibitions about using them when they will enhance the beauty of our gardens or the taste, health or yield of our crops.
That is not to say fertilisers are always necessary. Indeed in many cases there is no need to use them at all. Many garden soils are highly fertile; gardeners use manure and compost and good gardeners generally recycle soil organic matter and nutrients. Our soil can be a rich source of fertility. Why add more?

No need for fertiliser here
I have written before that my three naturalistic gardens have never had fertiliser. Neither does Cathi’s grass verge - indeed her complete garden -  nor my project in Lyndi’s field or in most of my own flower borders. Never-the-less in a year I almost get through a complete 25kg bag of yaramila fertiliser. Further on I will explain how.


No fertiliser for Cathi's new grass feature (although I am  pleased that her soil is naturally fertile)
Many gardeners seem to regard it as as a sacred beauty to supply fertiliser in their planting hole (or less damaging adjacent to it). Sometimes this might be a good thing but usually there is a greater need to get the plant established and perhaps apply a top dressing of fertiliser later. Fortunately many amateur fertilisers - but by no means all - are mere toys and like bonemeal will do little harm (bonemeal will do no good either). 

Objections to fertilisers discussed
This is the real thrust of my article today

Do they damage soil structure?
In the round this is nonsense. However in the big wide world there are thousands of soils of different nature and hundreds of so called fertilisers. Many are of dubious nature and some growers excessively apply them. There are bound to be instances where there will be an adverse reaction between between chemical and soil. Ammunition for the anti fertiliser lobby!
More usually fertilisers are neutral in effects on a soil’s physical condition. A few such as lime and calcium sulphate are applied to directly improve it.
A secondary effect of using fertiliser is that increased growth means more biomass is available to the gardener and farmer. When decayed organic matter is recycled there is improvement to soil structure. I previously wrote about how use of fertiliser contributed to the greening of Yorkshire’s pit heaps and creating ‘new soil’.
I have also written how my former allotment which never received imported organics over the years, that with sparing use of inorganic fertiliser, recycling of organic matter generated on site and a no dig policy, that it became black with organic matter.

What gives credence to the myth that fertilisers are bad for the soil structure is the way some farmers abuse them to maintain high yields and neglect other aspects of good soil management. (‘Good soil management’ might be as simple as minimum cultivation).
Claims of bad soil management is often true. I hope it does not apply to you.

They pollute water courses, ground water, lakes and the sea
This is a problem when farmers use large quantities, apply near water courses and apply them when leaching conditions prevail - usually in late Winter.
The main problem is soluble nitrate which arises from ammonium and other soluble nitrogen-containing fertilisers.The problem is more or less restricted to misuse of these ‘nitrates’ and from agriculture the problem is significant. 
Phosphates pollute water too and significantly so. Fortunately virtually all phosphate applied by growers is strongly absorbed by the soil and other than being hugely significant in contributing to the health and nutritional value in crops never leaves the ground. Phosphate pollution by farmers and gardeners only occurs when the nutrient directly bypasses the soil. Hang your head in shame if your compost heap made on hard standing leaches out direct to a drain! (In limited but sometimes significant cases phosphate can directly enter the water by wind blown soil erosion)
The main source of phosphate pollution is when phosphate rich detergents from your washing machine empties to your drain.

Organic gardeners should not be complacent about water pollution. Their organic manures release copious nitrate too

The amounts of fertilisers used by gardeners are minute compared to those used by farmers. I would suggest that gardeners less commonly apply them to not-yet-sown soil than do farmers and rarely as early as February - a time when leaching is most likely. Gardeners certainly don’t use great machines that fling fertilisers a long way. (My own garden gets a boost when the farmer fertilises his field).
Leaching under most growing conditions barely exists in Spring and Summer. Heavy rain washes nitrogen just a little deeper and hungry roots find it.
In my view a responsible gardener should have no reservations about his fertilser causing pollution.

Fertilisers are very energy intensive and add greenhouse gases to the atmosphere
There is no doubt that agriculture is energy intensive and uses a lot of fertiliser and diesel. In addition to carbon dioxide production, the greenhouse gases such a nitrogen oxides  - and methane from cattle - are also an issue.


My hard yaramila prill stores very well and a 25kg bag satisfies most of my annual fertiliser needs. (Lots of little bags of 'specialist' fertilisers is wasteful folly)
I wondered about the energy used in my own annual usage of 25kg of yaramila. In a very much ‘back of the envelope’ estimation I calculate that the manufacture and distribution of my 25kg bag produces the same amount of carbon dioxide as when 15 litres of petrol burns in my car. Interestingly the monetary cost of each is almost exactly the same.

Fertiliser might scorch my crops and cause ‘soft’ disease-susceptible growth
Unskilled and heavy use of fertiliser can damage plants.This is perhaps why weak toy fertilisers are often sold and recommended to amateurs. Not that misdirected chicken droppings will do no harm or that inferior lawn fertiliser spreaders cannot lead to disaster.
Some gardeners excessively use single nutrient fertilisers which are not balanced. High nitrogen alone especially if delivered in poorly illuminated greenhouse conditions does create soft and disease prone plants,
Nurserymen tend to use high levels of nutrients to achieve more speedy production of their plants. My all time least popular post is about ‘soft growth’ (there seems to be a negative correlation between my effort and a post’s popularity). I still wonder why when I buy a new dicentra at the garden centre it almost inevitably dies….
Sensible use of fertiliser grows better plants. This does not always happen.

Excessive phosphate application
Superphosphate was the first major manufactured fertiliser nearly two centuries ago. It increased yield and transformed farming. Phosphate is an essential nutrient. 
It is not a bad thing that it accumulates in the soil but there are circumstances where there can be too much. Most gardeners and farmers needlessly apply more to their soils. Unfortunately most general fertilisers include more phosphate than is needed. It’s not usually a problem, more a waste of resources.
Gardeners sometime find excess phosphate a problem when they attempt to naturalise wild flowers in grass. It is not that wild flowers do not like it, it’s just that nettles and coarse grasses like it better.

Effects on soil micro - organisms
In the rich cycle of organic life in garden soil numbers and composition of bacterial populations vary by orders of magnitude within just a few days of changing conditions such as warm, wet or dry. As long as we manage our soil well such changes do not matter a jot to our gardening. Fertilisers might do all of stimulate bacterial action, have no effect what-so-ever or inconsequential inhibition.

Inhibition of mycorrhizal fungi is a more serious concern. Fertilisers seem to break the faustian mutualistic contract between soil fungus and plant. If the plants’ need for nutrients is easily satisfied by a fertile soil - however this is achieved - then there is no need for the plant to donate to the fungus its carbohydrate resources and ergo less mycorrhiza.
In the wild mycorrhizal associations abound. For some plants they are essential for survival. Fear not, there are more mycorrhizal associations in your garden than you think - even when you use fertilisers.

So how do I get through 25kg of YaraMila in a year?


Buy this analysis for general use. Your local supplier might sell suitable similar products. Not usually sold at garden centres.
Other than iron sulphate on my lawn, yaramila is the only  fertiliser I use.


My pot grown tomatoes need generous applications
1. In my vegetable garden I might lightly scatter perhaps 30gm per square metre over any area I plant or sow. This may be before or after plant establishment and if I remember. Overwintered brassicas might get a little extra in Spring

2. On my sandy soil I find that top dressing my soft fruits such as blackcurrants, blackberries and especially raspberries works very well. My asparagus too. In recent years I have found that very early application in late February is best!


I top dress my contorted robinia three times a year
3. We have a large number of plants in display containers growing in soil. Nutrients do leach from containers and plants have a much smaller root zone than in the ground. Some of our tubs itinerate between indoors and outside. These might receive a top dressing as often as four times a year - as well as having been ‘made up’ with fertiliser content. This nutrient need would be greater if my plants were growing in regular potting compost.


Although I apply yaramila to my tubs of agapanthus I never need to fertilise those in the ground
4. I make up my own seed and potting composts from my own sandy soil. Most garden soils are unsuitable for this practice - but I think many gardeners do miss an opportunity. I sometimes add small amounts of yaramila. More sensible folk might use a slow release fertiliser.

5. I don’t liquid feed. I do not disprove of liquid fertilisers it is just that I am lazy (and mean) and top dress with fertiliser instead. All our pot plants have a scattering at some time or other. Even the orchid collection with a dozen granules or so per pot. They love it

6. A typical gardener might annually apply lawn fertiliser at say 20gm per square metre to their lawn. I have perhaps 600 square metres of lawn and grass paths embracing my borders.
I prefer to not box off my mowings and consequently return nutrients when I 'mulch mow'. Perhaps every other year an area of grass will receive a little fertiliser. Perhaps about 20gm yaramila per square metre. If a little goes on my borders when I fling it so much the better.
To apply this rate to the whole of my lawn would take 12kg of yaramila - half a bag!
In different circumstances Peter Williams applies 20gm/sq m of yaramila three times a year to his lawn - including midwinter!


This amount of homemade charcoal will be 'charged' with about 1kg of yaramila over the next year before I use it
7. Readers will know my penchant for making my own biochar when I douse the embers of all my garden fires with water. This wonderful medium initially is powerfully absorptive of nutrients and needs charging. If I have fertiliser handy when I pass my maturing pile it gets some.....

To buy yaramila you will need to find your local horticultural trade supplier or more easily order on the net

These links provide more detail

Why you do not need to buy lots of little bags of specialist fertiliser. 
My thing against bonemeal
All year round use of fertiliser
Why general fertiliser is suitable for your lawn
My penchant for using charcoal
Restoration of a slag heap 
Buying professional fertiliser
Crushed rock myth
Do fertilisers degrade soil? - whoops I have been repeating myself
My homemade soil potting compost
My post about hard and soft growth was a damp squib

This vigorous plant finds its own nutrient
So do these delicate ones
 Delphiniums need a little help on my very sandy soil
The annuals are rather lush on my former vegetable garden


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