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Care of Ashmead's Kernel Apple Trees

I've grown this splendid apple for around 11 years and I'm starting to get the hang of it. The original tree was found in Gloucester, UK about 300 years ago. It's often pretty dull in appearance and a difficult beast but it has a superb flavour which can resemble a fine pear! That's why it's still grown and has even spread to the USA.

I'm assuming that you know how to grow apples or have/will read up on it. What's here is information specific to this particular variety. Even more narrowly, I mainly stick to information that other web sites don't mention.

Brown rot
You might think that harvesting your own apples was a simple matter. Spot a glorious perfumed fruit, lift it off the tree and bite? Some types might be that easy - particularly the "earlies" but Ashmead's Kernel is a "late" and has very little smell. You're supposed to pick them mid-October but in my experience in Gloucestershire, that can be too late. Sure, by that time, some of the fruit you leave on the tree may be a lovely bright red there will also be black and brown spot/rot damage.

Another complication - but a good one - is that it can be like having two varieties of apple on one tree:

  • A mainly green-yellow and russet apple that ages into a sweet "pear drop" fruit. This is what the "books" tell you to expect.
  • A fruit with more red skin that is like a Cox in style but is both more acid and more sweet than a Cox. These can keep their powerful flavour for at least 6 weeks if stored cool.
Both sorts of fruit are well worth eating. Some never get any red skin no matter how long you leave them on the tree while others colour up quite early. There may be some correlation between red skin and sun exposure but I'm not sure.

Experimental bag and result
As an experiment, I put zip-lock bags on a few fruits on the tree and left them for another 6 weeks. This enabled them to grow larger and colour up with less damage. This gave me a fruit tasting like a sweet Cox. I stored two others but they didn't keep
Ashmead's Kernel are "keepers". It's not just that you can keep them, you must if you want to enjoy their magical "pear drop" flavour. However, those with a bit of red in the skin come off the tree with a strong sweet/sour flavour that you may enjoy.

Harvesting suggestions:

Start paying attention to the tree in mid-late August. In a year like 2011, some of the fruit will come away from the tree very easily but late September is more usual. Sample a few of the fruit - if it's a bit tasteless and maybe sharp, you're too early. In the next stage, the fruit becomes sweet and possibly too sharp for many palates.

Now you should watch the crop several times a week because it's very nearly ready to pick. The right stage looks like this:
  • A few, maybe 10% of the crop starts to show red flushing
  • Signs of damage increase, especially on the most ripe fruits
  • Harvest all fruit that a small child would be strong enough to pick
  • If a fruit shows resistance to being picked, leave it for your next picking session.
Any imperfect fruit should be eaten although but they may not be very good. Russetting isn't a problem. Store the rest. Like fine wine, they will improve with time.

This fruit looks a bit like a Cox, is rock hard and is quite sharp and probably sweet
A few weeks later, some of  the fruit softens slightly, russeting increases and the flavour is pear-drop
This one was retrieved from cool storage 07 Dec 13, was hard and still strongly sweet and sharp

From the cool box in the shed 24 Dec 13

The usual advice about apples is to store them somewhere cool and not too dry. This is supposed to maximise their life. However, what most people want is a steady supply of perfect fruit. Here's my system:
  • Store 1/3 of the crop in an unheated room - ready in 3-4 weeks
  • The next third, put in an insulated box in a cool shed - ready 5 weeks onward - update 14 Jan 2014, still getting good fruit although not as spectacular as earlier.
  • The final third should be refrigerated - perfect for Christmas? Update: This worked well until the end of November. However the fruit became progressively more rubberry,  leathery and tasteless. The answer may be to store the fruit in polly bags in the fridge to keep the humidity up. Update 2013/4 - the fridge stored crop are quite damp to the touch and have picked up a slightly "off" flavour. 
20 Dec 2011
As the fruit ages, the russetting may increase. For "pear drop" flavour, the "look" you want is rather tired and dull. Hard like a cricket ball may well be OK but best of all is a slight softness like a rubber ball.

The skin now doesn't look particularly edible so you can peel it but the flesh browns very quickly so I don't bother

It's a good idea to prevent apples in store touching each other. Traditional techniques are wrapping individually in newspaper or the use of special trays like in a greengrocers. I didn't bother and lost a lot of one batch to rot.

Imperfections and annoyances
  • Small isolated brown or black spots a few mm across but can grow to several cm This is either insect damage and/or the beginnings of brown rot. The damage is no deeper than the diameter. I've never found a "worm" inside these fruit. Cut out the damage try eating the rest.
  • Darkish, slightly sunken areas up to 5mm across. Appearance suggests something wrong just under the skin. This is probably bitter pit and may also be present in places you can't see.
  •  Light brown russet that may be quite coarse and spread to most of the skin during storage. This is normal. Peel before eating if you don't like it.
  •  No fruit one year, massive crops the next. See biennial bearing
  •  No/little fruit. Normal until the 4/5th year
Bitter Pit

Bitter pit

Ashmead's Kernel is prone to this disorder - small brown "dead" areas in the flesh but barely visible from outside. Scientists don't fully understand it but it seems to be down to lack of calcium, excess magnesium or nitrogen and poor/irregular irrigation. After some bad seasons, I instituted the following regime and it seems to be working well:

  • Nitrogen containing fertiliser in March and then no more
  • Don't use tomato or similar fertiliser containing Magnesium. Quite a lot of fertilisers do have Mg so check the label.
  • Unless your soil remains wet year-round, mulch the root area in March. Use good garden compost (NOT "multipurpose") Bark chippings are Ok. Go for 100mm.
  • If you have a drought, water the tree thoroughly.
  • In late June, spray the leaves with Calcium Nitrate solution according to the directions on the pack. You won't find calcium nitrate in every garden centre and one even told me it was now illegal! Repeat every 3 weeks until the end of August. The best choice of weather is dull. Bright sun or impending rain may cause problems.
  • Try and reduce biennial bearing
Biennial Bearing

Another problem that's common with Ashmead's Kernel. The tree is groaning with fruit one year and there's hardly any the next. You could ignore this quirk but you may find the larger crop suffers from Bitter Pit and doesn't keep.
  • At the beginning of June, inspect the developing fruit. If there isn't much, you're in for a lean year and there's not much you can do. The tree may be very leafy. What it usually means is that the crop the previous year was too big and the tree is taking a year off.
  • If there's a lot of tiny fruit, keep an eye on the tree for a few weeks as a many will fall off if there's wind. By the end of June, you need to start "thinning out" the fruit. 
How to thin out

The usual advice is to remove all fruit that's within 10cm of another one. That may be a lot of fruit - several hundred perhaps. You will worry that you're overdoing it but you're not. Since it's a lot of work, here's a cheat:
  • Give each branch a vigorous shaking
  • Quite a lot of fruit will fall off
  • Now go over the branch and apply the "no fruit within 10cm of another" rule
This technique gets rid of fruit that would have fallen off anyway in the next week or two. There's no point you culling them by hand.

Ashmead's Kernel ready for eating!
Prolific blossom in May


no2hs2 said...

We planted this tree some years ago and it did not produce at all for 4 or 5 year, last year we though it had come right but all the set fruit blew off. This year it has done brilliantly and we have over 140 lbs of these gorgeous apples. They make lovely juice and your keeping tips will be helpful. Nice post Thanks

Anonymous said...

What part of the country?

Steve said...

I said "in my experience in Gloucestershire" but perhaps your question was to no2hs2? :-)

wildwriter said...

I live in Cumbria and I have a large 20 years old Ashmeads tree. I can't reach the top branches - my fault for not keeping the pruning under control. It has many hundreds of apples so I take off what I can reach in October. These - in a bad summer like 2015 - are small. The couple of hundred remaining then grow in size (but still smaller than if grown in the south) and the top ones go red. I pick them on December 1st, or end of November if gales are imminent. Seriously - it's not supposed to grow this far north but it does and is so delicious, so who cares what you are supposed to do. Waxwings as well as blackbirds love them so I'm happy to leave a few at the top unpicked.

Tree Removal Queens said...

Wow! Really interesting post. Thanks for sharing

Sabine said...

I just planted four of these in the West Kootenay region of British Columbia. Keep your fingers crossed! We get hot summers (30+ degrees Celsius) and a few weeks of our winters usually go down to -20.
As an English tree, that might be too extreme, lol! But I hope not, this is the best apple I've ever eaten!

Unknown said...
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Unknown said...

I planted 6 of these trees about 12 years ago in Western NY USA our winter's have been mild but many have had cold below zero for several weeks it a time,this is an awesome fruit and it also bears our last name and makes it even more special

ripley said...

I planted 20 five years ago. Two have been lost. One just withered this year. The same thing happened to another a few years ago. What causes that? A blight? The trees were on M26 and are tip bearers. All are supported now. Really, because of tip bearing, the whole tree should be trellised at least until the tree grows stout.