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How to Feed Clematis

Tuesday, 16 May 2017 13:07:14 Europe/London

Feeding & Plant Health

Feeding

When it comes to feeding clematis, organic material is best: Clematis will benefit greatly from an annual mulch of manure/compost during the autumn and spring because it keeps the soil warm in the autumn to prolong root growth and used in the spring will hold in moisture preventing your plant drying out and of course provides excellent nutrient for the plant over a long period of time.Bonemeal

Bagged manure is fine but fresh manure should be left to rot and cool before use and don’t put it too close to the stems of the plant.  Additionally apply a good single handful of bonemeal when pruning has been carried out by working it into the soil around the base of the plant and watering in.

If your clematis are planted at the back of a bed or border (difficult to get to), then use 4 Westland Gro-Sure Slow Release tablets pushed just under the soil in February and during mid April a single handful of Sulphate of Potash can be applied. This clematis feed is high in potash and either of these fertilisers will improve the colour, size and quantity of your clematis blooms.

Alternatively from May use liquid tomato feed like Tomorite or Tomato Maxicrop once a fortnight until mid September.

For evergreen clematis it would be advisable to apply a good single handful of bonemeal in the spring and a single handful of Sulphate of Potash can be applied in the late autumn to help improve the winter or spring flowering.

To correct yellowing of the leaf you may use Epsom Salts which is a good general tonic for plants but is particularly good for nitrogen deficiency which clematis can be susceptible to.

Plant Health

Slug Damage

In the nursery we use natural predators for biological control of common pests to reduce the use of chemicals on our nursery.  If you notice a few ‘bugs’ on your plants, they may be friends, not foes!

Trying to keep a website up to date with all pesticide regulations is very hard so we advise you visit rhs.org.uk for the most up to date advice on which products to use on your clematis. Below is their advice on slugs and clematis wilt

How to control slug & snail damage on clematis?

The damage inflicted on clematis by these common garden pests can be devastating and the plant may appear to ‘Wilt’.

Check the clematis stems where the bark has been stripped off causing the stem to 'wilt'.  Also, the shoots emerging from below ground in early spring are particularly vulnerable.  The control of slugs and snails is essential to successful clematis growing so use whatever preventative methods you prefer.

What is clematis Wilt?

Clematis wilt is a disease of clematis caused by the fungus Phoma clematidina (formerly Ascochyta clematidina). Many of the large-flowered hybrid cultivars are very susceptible, but the smaller flowered species appear to be much more resistant. Wilting has long been recognised as a serious problem in clematis. And although it is known that the fungus Phoma clematidina causes clematis wilt, there are cases of wilting when the fungus is not present. Research has clarified two important points.

1. Wilting in large-flowered hybrid cultivars may be caused by Phoma clematidina

2. Wilting in resistant hybrids and species clematis is very unlikely to be P. clematidina, and is probably caused by environmental problems

So, although all wilting in clematis is often blamed on fungal infection, it is most likely to be caused by environmental problems, (unless it is wilting of the more susceptible large-flowered hybrids). Clematis is a plant which, in the natural environment, prefers a deep and fertile soil in a moist and shaded habitat. However, in gardens, clematis are often planted in shallow dry soils in exposed sites, often close to buildings. In such circumstances they suffer from root stress which contributes to poor growth and what is loosely described as wilt. Overall, infection by P. clematidina is a problem for the nursery trade and specialist growers, but relatively uncommon in gardens.

Symptoms

 The symptoms of fungal infection and environmental stress can be similar. The following symptoms are associated with fungal infection:

  • When fungal infection occurs through the leaves, these wilt and the leaf stalks turn black. Leaf infection is followed by rapid wilting of the stems
  • Fungal infection can also occur through stems. Freshly affected stems show black discolouration of tissue when split open
  • Young healthy shoots may be produced from the base of affected stems, sometimes from below ground
Non-chemical control
  • Try to create a suitable root environment by deep cultivation and mulching, to minimise root stress
  • If fungal infection is suspected, cut out all wilted stems back to healthy (non-stained) tissue and promptly destroy the affected material to prevent it contaminating the soil. New healthy shoots may be formed at ground level
  • Disinfect pruning tools to prevent spread of spores and avoid transferring infected plant and soil material to a new area 
  • Particularly susceptible cultivars include: Clematis ‘Henryi’, ‘Vyvyan Pennell’, ‘Mrs N. Thompson’, ‘Duchess of Edinburgh’, ‘William Kennett’, ‘Marie Boisselot/Madame le Coultre’, ‘Ernest Markham’, 'Comtesse de Bouchaud', 'Jackmanii' and 'Nelly Moser' are also susceptible
  • Resistant cultivars and groups include: Clematis ‘Avant Garde’, ‘Black Prince’, ‘Constance’ and groups montana, viticella (which is tolerant rather than resistant), diversifolia, integrifolia, macropetala and tangutica.

Chemical control

There are no chemicals available to treat clematis wilt.

Biology

Phoma clematidina can survive in the soil on dead plant material and organic matter. Infection occurs when spores are splashed or otherwise carried to leaves or young stems. Infection spreads rapidly to the shoots and stems, which when split open, are stained black. Infection causes rapid wilting and death. The root system is often not killed and young shoots frequently regenerate from or below ground level. The disease is not immediately fatal, but susceptible cultivars will usually die eventually.

Posted in Clematis Care By Peter Skeggs-Gooch

How to Plant Clematis

Tuesday, 16 May 2017 13:02:08 Europe/London

How to Plant Clematis

For a FREE download version of this Care Guide click here.

Planting

At Thorncroft Clematis we have been growing and selling clematis plants for over 30 years.
Here is an opportunity for us to pass on some of our best advice on how to succeed with them in your garden. 

The care of clematis is a big subject so click on the links below to skip to the parts you will find most useful. 
 

Careful planting is the key to success!

Hardening off  (November to the end of April)

Clematis purchased during winter through to April, must be hardened off before planting. Stand the plant outside in a sheltered position during the day but take into unheated cover overnight. An unheated greenhouse, conservatory or even a garage will be sufficient to prevent frost damage to the soft growth. The process should be continued for about two weeks before planting.

Planting Clematis in the Garden

The key to successful clematis growing is careful attention to the planting and soil improvement. Without proper soil preparation, even the best quality plants will not thrive or perform to their very best in your garden. An important thing to remember is that clematis like a soil which holds good nutrient but a soil that drains well, so that they do not become too wet.

1. If planting by a wall or fence - the hole should be dug approx. 12" (30cm) away from its base.
2. If planting by a tree - plant about 2 feet (60cm) away from the trunk leaning the cane of the clematis towards the support, try to plant on the north side where the host plant will then shade the root system of the clematis.
3. If planting to grow into a shrub - dig the planting hole just outside the ‘drip-line’ - this is outside the outer branches and lean the bamboo can into the shrubs lower branches.

Whatever your soil type, whether it is heavy or light, acid or alkaline, it should be improved before planting. A clematis does not need a particular soil pH, just good soil quality.

Clematis Planting method:

To start with water the clematis thoroughly before planting, maybe let it soak in a bucket of water but only while you prepare the hole.

1. Dig the planting hole much bigger and deeper than the size of the flower pot. 18”(45cm) diameter and depth is ideal. 
2. Break up the soil in the bottom of the planting hole and add well rotted garden compost or a good quality bag of compost. The best compost for clematis is John Innes No.3 because this is loam based and has a high food content. Compost for clematis needs to hold good nutrient as well as adding it.
3. If using manure, put a layer in the bottom of the hole, fork in well and cover with at least 2" of soil. Make sure it is rotted well and not hot or steaming. 
4. Sprinkle one good single handful of bonemeal into the hole and mix into the loosened soil. We stock Bonemeal in a 1.5kg Box.
5. Take the plant from the bucket of water (keep this water for later) and remove the plastic ties from the bottom 6 inches of the plant.
6. Remove the pot then carefully loosen the roots if they are in a tight ball.  This is essential to encourage good rooting and breaking some of the roots is not a problem, this will aid the development of new root growth.
7. IMPORTANT - Place the plant carefully in the hole making sure that the top of the root ball is buried about 3” (8cm) deeper than it was in its pot and re-fill the hole with a mixture of soil and compost, firming down by hand.Osmocote Exact Clematis Feed
8.
 Next place four  Westland Gro-Sure Slow Release Plant Food around the base of the plant by gently pushing them into the soil enough to cover them up.
9. Using the remaining water from your bucket, water thoroughly - especially if your soil is light and very free draining. Clematis planted by a wall, fence, tree or shrub, may need regular watering especially in its first year but be careful not to overdo it if planting in the autumn.

If your clematis is planted in a hot position, where the base of the plant will be baked by the sun for a large part of the day, place bark chippings or mulch around the base to provide shade for the root system.  This will help to keep the roots cool and moist avoiding the plant drying out so quickly.

We stock a range of useful products which you might need when planting your clematis or when preparing the planting area. Check out what we have to offer including our popular range of Care Packs right here in the Plant Care & Gifts  section.

How to Grow Clematis in ContainersClematis Pixie in Container

Choose a large container, preferably terracotta not plastic, at least 18"(45cm) deep with adequate drainage holes.  Put plenty of crocks, stones or gravel in the bottom to ensure good drainage and stand the container on feet or bricks to stop the drainage holes becoming blocked.

The best clematis compost is John Innes No.3 mixed with a good multi-purpose compost about 3 parts John Innes to 1 part multi-purpose.  Plant the top of the clematis root deeper in the new container by about 3 inches.

Check container grown plants regularly for watering needs, however be careful not to keep them too wet over the winter, and ensure the pot is draining freely!

Each February remove an inch or two of compost from the top of the pot and replace with fresh compost to which a single handful of bonemeal has been added, and water in. For the best results, put 3 Osmocote Tablets into the pot in March, then from April to the end of September we recommend using liquid tomato feed about once every two weeks.

Every four to five years root pruning may be necessary. During winter time when the plant is dormant take the pot off and cut away 2" - 3" of root from the outside of the root-ball.  Cut one third off the bottom, and re-pot with fresh John Innes No.3 compost.

Patio Clematis - Notes

To keep these clematis compact, we recommend HARD pruning in February / March and pruning hard again after the first flush of flowers has finished.
In other words - ignore the 'normal' pruning instructions!

For a comprehensive list of Patio Clematis see our Patio Clematis Page.

 

Tips for growing clematis.

1. TIPS for the, Atragene, Heracleifolia, Flammula, Tangutica Groups and also, rehderiana and other species.

All these clematis have very fine root systems and will not thrive in heavy soil, which is prone to water-logging.  They will actually be happier in poorer soils with very free draining conditions.

The herbaceous Heracleifolia Group require hard pruning each year but this is much better left until April when the weather has improved. Do NOT prune these hard in autumn or winter when tidying other herbaceous plants as the Heracleifolia Group over-winter better with the old growth left intact.

2. TIPS for the Evergreen Clematis including the Armandii, Cirrhosa and Forsteri Groups.

Please do not grow these clematis in open, very windy situations, or in heavy soil which is prone to water-logging, as they will not appreciate it and will fail to thrive and possibly die.  Instead, give them the shelter of a wall or sturdy fence and ensure the soil is very free draining.  Occasionally some leaves will die off, this is natural and they can be trimmed off.

Evergreen clematis have a natural dormant period which is around mid-summer when they look ‘tired’.  In extreme heat, cirrhosas may drop their leaves, whilst napaulensis does so every summer.  Do not water too much at this time, but give them two or three doses of liquid tomato feed at fortnightly intervals which will perk them up and will encourage them to produce fresh leaves and flower better later on.

Forsteri Group - Other than in milder climates (especially in the UK) we recommend that you grow all the clematis in this group in free-draining soil and give them the benefit of a sheltered aspect.  The compost for containers should ideally be very free draining and mixing in a few handfuls of horticultural grit or perlite will help.  Make sure the pot can drain freely and reduce watering in the autumn because they over-winter better if slightly dry, rather than too wet!

3. TIPS for the Florida Clematis

These stunning clematis are very prolific and can flower for a very long time when given the right care and attention, so here are my top tips for the florida clematis. 

I would recommend growing florida clematis in large pots because they perform very well and they make a stunning display on a patio. Stand the container on the patio from late February to early October and then move it into a sheltered corner or cold glasshouse to over-winter. They will not need heated conditions during the winter, just shelter and if taking them undercover they will probably continue flowering.

In early March the previous season’s growth should be hard pruned down to approximately one foot (30cm) from the soil level and a fresh ‘top-dressing’ of compost and bonemeal can be applied to the container. Use Osmocote tablets for consistent feeding through the year. 

Avoid keeping the florida’s too wet over the winter, on the other hand they must not be allowed to dry out completely. Always ensure the pot drains freely and each year harden the plants off during late March as described above.

When planting florida clematis in the garden they will require the shelter of a south or south – west facing wall, with good free draining soil. A sheet of bubble plastic or a double layer of garden fleece draped across and pegged into position will keep the worst of the winter weather at bay. This protection can be removed during early March so that hard pruning can be carried out, then feed with a single handful of bonemeal and water it in. Replace the protection until the worst of the weather has passed.

For further cultural hints see – Growing Clematis in Containers.

Clematis for Hot Climates

We have many customers who garden in countries with warmer climates like in southern France or even hotter such as South Africa or southern Japan. We are grateful to them for giving us feedback on what does well and what does not in these hotter climatic conditions.
Generally we would suggest the following as a guide to those types that are happier in a warmer climate. However, all individual environments do differ, so we cannot guarantee success in any particular location.

Have a look at our page of plants for Dry / Hot Area's.

Keeping the clematis moist at the root is key. Ensure that the compost does not dry out, nor become waterlogged from too frequent watering, then most clematis will cope with reasonably high summer temperatures.
Growing them in pots or containers of some sort is often a better way to ensure good soil and moist, yet free-draining conditions. We understand, for example, that the local soil in Madeira and parts of South Africa is not ideal. There is really no need to shade the roots - although it can help to retain moisture, it can also harbour slugs and other pests.
Most general advice is still the same as in England; Water the plants daily; feed them every two weeks even when they are flowering, and keep pale coloured types that are prone to fading, in shade. (Guidance on Aspect is given in our catalogues - both printed and online).

As a guide, based on feedback from customers, you may like to try the following:
Most of the species, such as terniflora, serratifolia, viticella and heracleifolia. 
Cirrhosa and other evergreens, but they may exhibit summer dormancy, losing their leaves in the hottest months.
The Tangutica Group will be fine in drier soils but high humidity may be a problem.
Montanas generally, although they do need a good supply of water especially as they can become very large.
Most large flowered types, but treat all as hard-prune (Group 3), ignoring UK guidance, to avoid too much dead foliage after the early flowers. They should flower again 6 - 8 weeks later.
The Integrifolia Group and Texensis Groups, but these must be kept moist at the root to avoid mildew problems.  

Those not suited are the Alpina Group, especially in hot, humid climates such as Japan.

Clematis for Windy Area's

If you are looking for clematis to grow in a position that is exposed to a lot of wind, those in the following groups will cope best. As well as these groups you can use most Hard prune clematis except the category Florida. Have a look at our Windy Aspects page.

Atragene Group - Spring flowering cultivars with nodding bell-like flowers. They are all very hardy, but require a free draining situation. They do not need the 'rich' growing conditions or deep planting that the large flowered cultivars prefer.

Diversifolia Group - These herbaceous cultivars are clump-forming scramblers, or semi-climbers, derived directly, or indirectly from the integrifolia species. In general, they have non-clinging stems and they can be allowed to scramble in herbaceous borders. Alternatively, they can be used to clamber through open shrubs, small trees, rambler and shrub roses or obelisks. They are all hardy, very free flowering, trouble-free clematis and are highly recommended. All the clematis in this group are suitable to use as cut flowers.

Integrifolia Group - These herbaceous cultivars are clump-forming scramblers, they have non-clinging stems and can be allowed to scramble in herbaceous borders. They are good 'front of border' plants and also make excellent companions in beds of bush roses. They are exceptionally hardy, very free flowering and as with other herbaceous plants, they die back in winter. They are all suitable to use as cut flowers.

Viticella Group - They are all extremely hardy, very free flowering, their pruning is simple and they cannot be recommended highly enough. Especially useful for people new to growing clematis as they are extremely tolerant of what the gardener does to them!

Tangutica Group - The clematis in this group are extremely useful in the garden, providing colour and interest from mid-summer through to late autumn, with most producing excellent seedheads for added interest in the winter months. They cope happily with poorer growing conditions and are drought tolerant.

© Thorncroft Clematis 2016

Posted in Clematis Care By Peter Skeggs-Gooch

Pruning Heracleifolias and Winter Flowering Clems.

Tuesday, 25 April 2017 13:11:15 Europe/London

Pruning Heracleifolias and Winter Flowering Clems.



Now is the time to give your Heracleifolia clematis their hard prune.  The Heracleifolia Group are those clematis which are considered as herbaceous sub-shrubs, they are clump-forming and have strong woody stems, in fact they are most unlike what we traditionally think of as clematis.

Cassandra

Image of Cassandra.

In the previous blog ‘Clematis Pruning’ I suggested that you semi-prune these, just enough to remove about half last year’s growth to tidy them up a little.  I always prefer to prune this group of clematis in two stages because I have found that the Heracleifolias will tolerate a late frost better if you have left some old wood on them. The dead leaf also makes a good cover over the crown of the plant through the winter, protecting the plant from getting to wet at the base of the stems.


So about early April is a good time to give these their final prune for this spring and all you need to do is prune off the old stems just above the highest new shoots and remove any dead leaves that might still be lingering around the clump, as this will help to deter slugs and snails from setting up home there.

HeracBefore

Image of Heracleifolia Before.

Heracleifolia

Image of Heracleifolia after.


Now give them a good single handful of bonemeal and work it into the soil around the base of the plant, then add slow release fertiliser and water it in if there is no rain forecast for a few days.  There is nothing more to do now except wait for their lovely display of flowers in late summer.  These are such an easy, worthwhile group of clematis to grow - they will cheer up any border of the garden and, especially as several of them are fragrant!


Over the next few weeks, is a good time to reduce some unwanted growth from any of your winter flowering clematis, namely the evergreen Cirrhosa Group (balearica, ‘Freckles’, ‘Jingle Bells’, ‘Wisley Cream’ etc.), napaulensis and ‘Winter Beauty’. Their pruning, if it is needed, can be carried out any time after they have finished flowering, indeed, the same will soon apply to the Armandii Group, ‘Apple Blossom’ and ‘Snowdrift’ etc. They will now be at, or coming to their peak of flowering, so their pruning should be delayed a few weeks until all the flowers have finished.

Basically, with any of these evergreen clematis, they do not have to be pruned, but only when the gardener feels it is necessary, for instance, if the plant has more than filled its allotted space in the garden.  Really, the most that is normally required is to prune off any excess growth to keep it within bounds, nothing more than a good ‘hair-cut’!

You will then find that in a few weeks the plant will make some fresh growth that can be trained in, where you want it to go; maybe to fill in any gaps in the old stems and generally to make the clematis look better.

If, for any reason you need to cut down into the very old woody stems, most of these evergreens will cope with this quite well, apart from the Armandii Group which can take exception to very severe pruning and refuse to reshoot.  So be careful with these, my suggestion is to cut no lower down the stem than where there are leaves.  Cutting above leaves should encourage the clematis to reshoot, but perhaps the safest is to avoid having to severely prune the Armandiis.  Therefore, if growing space is somewhat limited, it would be better for the plant to be cut a little back each year, which should hopefully avoid the need for more drastic measures in the future.


TIPS
Late April or early May is the time to start liquid feeding container grown clematis – Tomato feed is excellent.  Once a fortnight should be enough to encourage a really dazzling display of flowers.

Look out for new stems that are waving around in the air. They grow so fast at this time of year, and they can be broken off in a strong wind, so make sure to train them in or tie them to their support carefully with split rings.

Armandii Apple blossom

Image of Armandii Apple Blossom.



Posted in Clematis Care By Peter Skeggs-Gooch

How to Prune Clematis

Wednesday, 8 March 2017 22:46:13 Europe/London

Pruning is one of my favourite jobs in the garden, I love to get secateurs, or better still, loppers, in hand, especially when a good tidy up becomes essential!   Late February is a good time to prune the majority of our clematis – those that need either a light or a hard prune (pruning groups 2 and 3 if you prefer to work in numbers).

Hard pruning is dead easy, it is relatively quick, not too many decisions have to be made and it is excellent therapy for a day when you maybe have ‘got out of bed on the wrong side’!  Whereas light pruning requires some decisions regarding height, shape etc., it is fiddlier and therefore requires doing on a day when all is well with your world and patience is plentiful!

 

I will keep this as clear and simple as possible

Lets deal with hard pruning (group 3) first – this group includes all the Late Large Flowered Hybrids, the Viticella, Integrifolia, Texensis, Flammula, Florida, Tangutica, Diversifolia and Heracleifolia Groups. 

The hard pruning will vary, very slightly, between the groups – we will start with the Late Large Flowered and Viticellas first as the technique is exactly the same for both groups.

Start at soil level and track up each stem looking for a good set of viable buds in the leaf joints, leave two sets of buds and prune off just above the second set – this will be anywhere between 9” and 18” above the soil.

Madam Julia. Viable buds Viable buds
Viable buds on Madam Julia. Viable Buds

 

Try to leave two good sets of buds as insurance because the top set will shoot away quickly once the weather warms up and could get ‘nipped’ by a late hard frost.  If this does happen, don’t worry, the lower set of buds will have remained dormant so you can prune any damaged growth down to them and all will be well.

Having pruned through all the stems all you need to do now is gather the rubbish stems together and pull them away from their support – this is the best bit!

 

Clematis in the Integrifolia, Diversifolia, Flammula and Texensis groups usually die down each winter, often to soil level and therefore need treating slightly differently at pruning time.

Again start at soil level, if there are viable buds along the stems, prune as previously described.  If there aren’t, simply prune off about 3” above the soil – there will be new shoots at, or just below soil level which will quickly make new growth to provide this year’s blooms.

Integrifolia Alba Pruned

Integrifolia Alba pruned.

Varieties in the Tangutica group are unlikely to have any visible signs of viable buds and should therefore be pruned straight through about 18” above the soil – garden shears are useful here which saves time!  The plant will look dead for weeks but will suddenly burst into new growth as the weather warms up.

Clematis in the Heracleifolia group should only have their old flowering wood ‘topped’ just now – you to prune them later in the spring, early April is ideal. See the Pruning Heracleifolias and Winter Flowering Clems. blog for instructions but for now, simply reduce the stem by half, this will help to tidy the garden up.

Clematis in the Florida group are not 100% hardy, but if you are fortunate to live in a milder area, or if you have a very sheltered garden then maybe you have these planted out.  Most of us however, have to rely on growing these exotic beauties in pots so that we can move them into a greenhouse or conservatory to overwinter.  Whichever, you may find that the plant has remained semi-evergreen, or even still in flower – but you must prune it now!  Simply prune off above a set of buds or leaf joints around 12” above the soil.

If you simply do not have the time, or even the patience to sort out your different varieties of hard pruning types you could just gather the stems together, prune through about 12 – 18” above the soil and remove the top-growth – that would be sufficient to tidy the plant and it would still be fine!

 

Light pruning is for your Early Large Flowered Group –

These clematis often make a large ‘ball’ of growth at the top of the plant that I refer to as “the birds nest”! The easiest way to deal with these clematis is to roughly cut off the top 1/3 of the stems in mid-February (St. Valentines Day maybe!) Return after a couple of weeks once new shoots have started to appear.

This time, start at the top of the plant and track down each stem pruning off dead growth just above the first viable set of buds in the leaf joints. The height at which these buds appear will vary and you may find some stems with no viable buds until low down near the soil. Don’t worry, this is quite normal, prune these stems just above the low buds then very carefully remove the cut stem from amongst the ‘good’ ones. It will be worth the effort as this method will ensure new fresh growth is made from top to bottom of the plant, in turn this will encourage flowering up and down the plant.

Keep in mind that clematis are tolerant of most things the gardener does to them and I do not know of an instance where a clematis has died simply because it has been pruned incorrectly!

Light Prune Complete

Light prune completed

Tips: - Now is the time to feed all your clematis a single handful of bonemeal.  Scatter it around the base of the plant and carefully work it into the soil, but do avoid knocking off any freshly emerging shoots.  If rain is not expected within a day or two, water it in.  Bonemeal (not Fish, Blood and Bone) will give a good slow start to your clematis.

You can also add some slow release fertiliser tablets to those clematis that are hard to get to, for example at the back of the border, this saves you having to scramble around the borders to feed them through the summer.

I hope this helps you get through the pruning of your clematis more easily and if it makes you feel better about it, before you start, just tell them, ‘Peter said so!’

Posted in Clematis Care By Peter Skeggs-Gooch

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