HOW TO CARE FOR RASPBERRIES
By David Marks
Once they are planted, raspberries are low maintenance fruits but they do require attention a few times during each season. Pruning is required once a year at different times for autumn and summer fruiting raspberries.
Raspberries are water hungry plants so mulching at the beginning of each season is advised. In dry weather they will require watering especially when the fruits are forming. Feeding is also needed.
Summer fruiting raspberries will need to be tied into supports during the year.
FEEDING AND WATERING RASPBERRIES
As we mentioned on the previous page raspberries are water hungry plants, in particular when the berries are forming. The crucial period for summer-fruiting raspberries is mid spring to early summer, for autumn fruiting raspberries it is late spring to late summer.
However, for the healthiest raspberry plants keep the water supply constant at all times of the year including non-fruit producing times. From mid-autumn to mid-spring natural rainfall should be sufficient by itself.
With water increasingly becoming a valuable and costly resource, mulching is an increasingly rewarding gardening activity. It reduces water loss from the ground considerably and also provides a small but constant supply of nutrients.
Mulching of the soil around raspberries will reduce the need for watering. Simply lay well rotted organic matter on the soil around but not touching the stems. A depth of 10cm / 4in would be ideal but any depth of mulch will be beneficial. The best time to do this is in just after feeding the plants (see three paragraphs below).
Personally I would avoid putting mulch on clay soils when growing raspberries. Clay retains moisture and can become waterlogged if mulch is applied.
If well-rotted organic material is in short supply grass cuttings will do a good job. Previously it was thought that as grass rotted down it would leach the soil of nitrogen. Recent, rather more scientific tests, have now proved that this is not the case. The reduction in nitrogen is very small indeed and the benefits of mulching far outweigh any loss.
In very hot spells even mulching will not be sufficient and then a weekly watering will be necessary to get the best fruits from your raspberries. The rule with watering is to provide lots of water but at infrequent intervals. A thorough weekly watering during very warm weather should be enough for almost all conditions in the UK.
Apply an organic feed such as bonemeal or blood, fish and bone (two handfuls per square metre / yard) in the third week of 2015. This will release nutrients slowly over a couple months. Two more feeds of the same in the third week of May and the the third week of July will give your raspberries all the nutrients they need.
Pruning raspberry canes is easy, the only complication is that autumn fruiting and summer fruiting raspberries are pruned at different times of the year and in different ways. The reason for pruning at different times is that summer fruiting raspberries produce fruit on stems that grew the previous year whereas autumn fruiting raspberries produce fruit on canes that have grown in the current year.
First, the easier to prune are autumn fruiting raspberry canes (these are sometimes referred to primocanes). The canes are fully dormant in midwinter and this is the time to prune them. Using a sharp set of secateurs cut all the canes to a height of 15cm / 6in and the job is done! Some recommend pruning the canes back to ground level but leaving a 15cm stem allows you to see exactly where your raspberry canes are and it's then easy to avoid trampling them when they start to grow again in spring.
Summer fruiting raspberries (these are sometimes referred to as floricanes) should be pruned soon after they have finished producing fruits. In your area this will be approximately the third week of August.
To understand how to prune summer-fruiting raspberries it’s best to know that they are really biennials – in other words they grow in the first year and produce fruit in the second year.
Prune out all the canes which have provided fruit this summer but leave the canes which have not produced fruit. It’s easy to see the difference, the new canes will have much greener and lively looking stems compared to the canes which have borne fruit this year (see the picture above which can be enlarged by clicking on it). Prune the canes to ground level with a pair of sharp secateurs. While doing this look out for any canes which have grown this year but look weak – prune these back at the same time.
When you have finished pruning you will end up with a pile of canes which are very useful for supporting dwarf French beans. Just stack the canes in a dryish part of the garden and use them next year. As the raspberry canes grow throughout the year, summer fruiting types should be tied in to supports at least twice depending on how high your variety of raspberry bushes grow.
Trial and error is the best way to find out when raspberries are ready for harvest. Colour of the berries cannot be used as an overall guide because different varieties have different coloured berries. When you pick a raspberry, it’s ripe if the berry comes off easily and the white central core remains on the bush. If the berry squashes when you pull it off then it’s probably over-ripe.
It’s a temptation when harvesting raspberries to pile them high into containers. Don’t do this because the raspberries at the bottom of the container will be crushed by the weight of the top raspberries. Try to harvest your raspberries when they are dry, wet raspberries deteriorate quicker than dry ones. Layer them two, at most three, deep in shallow containers, store them in shade whilst harvesting and get them into the fridge as soon as possible. A ripe raspberry will last two, possibly three days in the fridge before it starts to deteriorate significantly.
Frozen raspberries will last three or four months in the average freezer. The freezing process does damage the texture of raspberries so frozen raspberries are ideal for jam, fruit drinks and flavouring. Frozen raspberries can be defrosted in the fridge and used as a topping for morning cereals (our favourite) and also to be added to plain yogurt to give a fruity taste.
HOW TO PROPAGATE RASPBERRIES
Raspberries are easier to propagate than many think. Indeed, if left to their own devices they can quickly overrun large areas of a garden. Raspberries produce underground suckers which spring up anything up to a metre / yard from the parent plant. Simply dig up a healthy growing sucker with the roots as complete as possible and plant as if they were a shop bought plant (click here for detailed planting advice).
The best time to propagate raspberries is December time but in reality these plants are so strong growing that they can be planted at any time of the year as long as they are initially supplied with lots of water.
COMMENTS / QUESTIONS LEFT BY OUR READERS
|Date: 9 April 2019
|QUESTION: On 2 Jan 2018 your answer tomorrow included the comment that on your allotment you had both summer and autumn raspberries in a block, and consequently could not distinguish which was which. You stated that you pruned them both same. I have the same problem. What method should I use to, prune them, and when?
ANSWER: I alternated between the two methods. So in first year I inherited the allotment I cut them all down in winter to an inch or so above ground level (as per autumn pruning). In year two I would prune them in late August removing only the older looking canes (as per summer fruiting). This seemed to work OK for me although I had inherited a sizeable block of raspberries, more than the two of us could eat.
Having learned my lesson I have planted the two types separately on my new allotment with no chance of them meeting up. This has allowed me to compare the two types and it seems clear to me that already at this time of year in spring the summer fruiting variety is much taller compared to the autumn fruiting ones.
In theory this might allow you to dig up one type based on height in spring and move them away. However, I certainly wouldn’t bother. Anyway, some of the roots of the “to be transplanted” type would almost certainly remain and it would take several years to separate them out in any meaningful way.
|Date: 5 May 2018
|QUESTION: When you say mulching is needed at the start of every season, does it mean the remaining mulch needs to be removed at the end of the season?
ANSWER: Don’t remove the old mulch, it is still doing its job. If there is a lot of it then you may not need to mulch every year. It all depends on how much mulch you put down the last time. Any organic mulch will break down over time so the mulch will need to kept topped up.
|Date: 15 April 2018
|QUESTION: I’ve got new shoots growing from my rasps but just a few. If I mulch the ones area, leaving the shoots I can see clear, will this suppress any other shoots so all I Will get is what I have now. I’m keen to mulch as weeds are an issue. Sorry for the daft question, this is only my second year at this
ANSWER: Not a daft question at all. Raspberries are very tough plants and will easily push their way through a couple of inches of compost / woodchip / barkchip mulch. They wont push their way through fabric or plastic barrier mulch.
|Date: 14 January 2017
|From: Dave N
|QUESTION: I forgot to prune my Glen Ample raspberry, should i leave them or prune them back and if so how much thank you.
ANSWER: I would prune them as soon as you can, it’s not ideal but no great harm will have been done. Prune them as described in the main article above for summer fruiting raspberries.
|Date: 11 September 2016
|QUESTION: I planted summer and autumn raspberries in our school garden. Two canes have fruited, the others have not. I assumed that the canes which fruited where the summer variety, however, your webpage says that the summer variety does not produce fruit in the first year. As I have not labelled my canes, I have no idea which is which. Can you tell me at what time of year I would expect the autumn variety to fruit and whether the canes that have fruited are in fact the autumn variety?
ANSWER: In general summer fruiting raspberries produce fruit on canes which grew in the previous year. They do sometimes break this rule for reasons not fully understood.
If you have mixed up summer and autumn fruiting raspberries it’s going to be impossible to separate them as far as pruning is concerned. They will put up new shoots several feet away from the mother plant and the area will very quickly become a mixture of the two.
This had happened to me on an allotment I inherited many years ago – I never sorted out which was which. My approach was simply to prune away any stems which had produced fruit in that year and any which were clearly brown stemmed rather than new green stems. I did this in early September every year. It’s not perfect but it worked for me.
|Date: 10 September 2016
|QUESTION: I have newly planted summer fruiting raspberries. But this year I had logs of fruit. Do I prune all the canes down to soil level?
ANSWER: Prune out all the canes which have provided fruit this summer but leave the canes which have not produced fruit.
|Date: 10 July 2016
|From: Mike E
|QUESTION: I have an established bed of Glen Ample raspberries. I am picking fruit at the moment and have noticed that flowers are forming on the new canes that are coming through. Do I leave these to perhaps fruit or should I nip them off?
ANSWER: I would leave the flowers on. Although Glen Ample are summer fruiting you may well get a few fruits from the new canes later in the year. Leaving them on won’t weaken the plants.
|Date: 13 October 2015
|From: Mike S
|QUESTION: After pruning do u feed or mulch raspberries?
ANSWER: You can, and it won’t do any harm. But by far the best time to mulch and feed is early spring when the plants are starting into growth.
|Date: 28 July 2015
|QUESTION: I want to relocate some raspberry bushes – I am assuming that they must be summer fruiting as they are fruiting (although not very well). When would the best time to dig them up?
ANSWER: The best time is probably around December when they are dormant. But as long as you wait for them for them to finish fruiting, any time from then until March is fine. Why not wait until they finish fruiting, prune them as described here, wait a month and then move them. Raspberries are very strong growing plants, just make sure that they have sufficient water.
|Date: 14 July 2015
|QUESTION: I have summer fruiting raspberries, only small plot and new growth spreading, how can I contain in a small area?
ANSWER: With difficulty is the honest answer. Raspberries can become invasive. Constant cutting out of new shoots is one answer but the job will always need to be done as long as you have raspberries.
The more long term solution would be to dig up all the plants (try to remove all traces of their roots), dig a trench about 60cm deep and line it with strong plastic. Punch small holes in the base of the plastic to allow drainage. Refill the hole with the soil and then replant your raspberries. The best time to do this is around November to February time. Apply a good mulch around the plants but not touching them. Raspberries are extremely strong growing plants and the check to their growth will be minimal, if any.
|Date: 4 June 2015
|From: Allen Tinham
|QUESTION: If 1st year canes start to flower should they be nipped off? Some canes I bought are shooting new growth from canes and also from ground should I let them fruit?
ANSWER: Leave the flowers on and if the new canes start to flower let them do that. Raspberry plants are as tough as old boots and will have no trouble establishing themselves even if they fruit in the first year.
|Date: 27 June 2015
|QUESTION: Will my long cane, Glen Lyon, raspberry plants fruit this year? I ordered them the start of May but unfortunately they didn’t arrive until June. Just short of a month ago. Problem is they are showing no sign of life. Is it to soon? Hope you can help.
ANSWER: I doubt very much if they will produce fruits this year. Planting in autumn often results in some fruit the next year but less than a month is too much to hope for! I am sure they are currently putting down roots and may not show signs of life until next spring so don’t be concerned.
In this dry weather be very sure to water and mulch such young raspberry plants. June is not the best time of year to plant them. Expect a small crop next year and a much larger crop the next year.
|Date: 31 August 2014
|QUESTION: Can you give me the names of which raspberry are summer and which are autumn?
ANSWER: The most common ones are already described on our raspberry varieties page. If you want to know about a specific variety then let me know.