Episode 24 Gardeners' World

Hello. Welcome to Gardeners' World.

This week, we are coming from two Royal Horticultural Society gardens,

at Wisley and Harlow Carr.

Carol and I will be enjoying all the excellence and the expertise to be found here.

In fact, we will be tapping into that expertise to directly answer

some of the questions that you have sent to us.

I shall be based here, at Wisley, in Surrey.

And I'm here in Yorkshire, at RHS Harlow Carr,

looking at some of the plants

that thrive in the much harsher climate.

Harlow Carr sits on the edge of the Yorkshire Dales.

It's the most northerly RHS garden.

And while I'm here,

with the help of gardening experts who are actually on site,

we're going to try to answer some of the dilemmas that have been sent in

by viewers gardening under similar harsh conditions.

I shall be looking at fruit and vegetables.

I'll be seeing how the growing year has been at Wisley,

and also getting some tips and hints, and also getting ideas

for a fruit that I don't grow at Longmeadow but I certainly plan to.

Wisley's plant collection is one of the largest in the world

and is made up of 172 acres of gardens,

with half an acre devoted to growing vegetables.

Many of the plants here in the vegetable garden,

in fact right across Wisley, had been awarded an AGM.

This is a result of the trials that are going on here all the time,

looking at the garden worthiness of plants.

Now, AGM stands for an Award of Garden Merit,

and the criteria include its disease resistance,

its ability to cope with drought or different soil conditions,

and above all, that the plant does what it says it's going to do,

that it is reliable and consistent and can be trusted.

Of course, vegetables are grown to eat,

and AGMs only look at the way the plant grows.

It doesn't give any opinion or judgment on the taste, which is essential.

And the man here at Wisley in charge of the vegetables

is also passionate about taste.

Mario De Pace used to be a chef before he turned to horticulture,

and he works hard to ensure that the vegetables grown here have the best flavour possible.

Mario, for a lot of us growing vegetables,

we've struggled this year. It's been difficult.

So what has gone well for you?

The cucumbers have been quite a success,

as you can see.

How do you get cucumbers looking as healthy

and as fresh with so many fruit at the end of September?

Well, the secret, my secret, is that I do two plantings of cucumbers.

The first one, until the end of July, and then come mid-July,

I sow fresh seeds to be ready for planting at the beginning of August.

-And they are so productive.

-Yes, indeed, especially the little one.

-If you would like to taste this.

-Of course!

Cucumbers are ready when the top is roughly the same size as the bottom.

That's a good tip, to know that. So we'll take it off there.

Eat the end. And you don't need to peel this one at all?

No, definitely not.

-That's delicious.

-And you can see the seeds,

they haven't formed at all.

It's seedless, it's tasty, it's fresh.

-Go on, you have some.

-Thank you very much.

-That's fabulous, isn't it? A taste of summer.

-Ideal for lunch.

-Hmm.

They are growing in grow bags. Do you have to water them a lot?

Yes, that's the secret of growing good cucumbers.

Keep up with the watering, and feeding as well.

-It's very important.

-How often?

I feed them with high-nitrogen fertiliser almost on a daily basis.

-Really?

-Yes.

I love tomatoes and I love growing them

but the truth is, the very best British tomato

is not often as good as the average Italian tomato!

You're an Italian, you know about tomatoes.

Do you think there is a good all-round variety?

Yes, this one, "Cristal", is one of the most reliable varieties.

It's quite well resistant to pests and diseases

and it's a good cropper.

-Is that an AGM plant?

-It is an AGM variety, yes.

This is a good all-rounder but I want to know about you.

-What's your favourite?

-OK, OK.

-So...now, what variety is this?

-Try this.

This is called "Red Pear".

I don't know this one.

It's got a nice thin skin. You feel it. It's...yeah.

Again, I like it in a salad, this one,

just a bit of mint, salt, pepper.

It's nice and meaty, isn't it?

Yes, but if you make a tomato sauce with this one,

you get the creamiest tomato sauce that you can think of.

-Really?

-Yes.

-I love that. "Red Pear"?

-Yes.

To avoid blight, what do you do about that?

I'm but very careful with hygiene, you know,

because the spores will attach to your clothes

and if you then go and get in contact with the leaves,

then you transmit the blight.

And I'm very careful that I do my tomatoes first thing in the morning,

and then close the door.

Now, tomatoes, same family, you've got potatoes.

-You cut all the horns off.

-Yes.

-Why is that?

Because they were... We had the same problem as everybody else, blight.

They were affected by blight,

so in order to do a damage-limitation exercise,

I cut off the tops as soon as I spotted the blight,

so that the blight didn't have time to go down the stem

and affect the tubers.

Now this is a variety called "Mayan Gold".

Yes, yes, this is one of my favourite varieties.

-In my opinion, it's the best one for chips.

-For chips?

-For chips.

Oh, it's not hard to... They've got a nice gold colour, there.

-They're beautiful potatoes.

-And they taste fantastic.

-Look at the colour of the flesh - golden.

-It is, too. How lovely.

I will definitely grow these next year. They look really good.

Thank you so much. I could spend all day with you!

You probably wouldn't want to spend all day with me, but it's...!

I wouldn't mind some help digging out the potatoes.

THEY CHUCKLE

Of course, it's not just vegetables that get trialled here.

A lot of our familiar border plants go through the same process

and receive the AGM.

Now, Carol is up at Harlow Carr

and she's doing what she's been doing all year -

looking at plants growing in the wild and seeing how Harlow Carr

incorporates them into their overall planting schemes.

On this gently sloping but exposed site lies an ancient meadow

that long pre-dates the gardens here.

It's packed full of all manner of perennial wildflowers

and beautiful grasses.

Earlier in the year, the whole place would have been a sea of scintillating colour,

with wild orchids, yellow rattle.

Now everything's bronze and soft browns

and those flowers have been replaced by seed heads.

It's harvest time.

The closer you look, the more you see.

There's such an amazing diversity of beautiful seed heads in here.

This is yellow rattle,

so-called because its seeds really do rattle around

in those dry, papery sheaths.

Its roots feed on the roots of grasses,

and that means that it's a very important constituent

in hay meadows and wildflower plantings

because it actually suppresses the growth of those grasses,

enabling wildflowers to really thrive and flourish.

So, too, things like this centaurea, this knapweed.

Really tough as old boots.

It'll grow absolutely anywhere.

And up here, in North Yorkshire, that really is an issue.

Suzanne and Lance Cunningham have been in touch with us.

They garden at Darwin in Lancashire, on the edge of the Pennines.

You don't get much more exposed than that.

We live on top of a hill. We're about 880ft above sea level.

And some of the plants, it really affects them badly.

Our dilemma is that we buy a lot of plants, put them in the front,

they seem to last for about one season and then die.

The problem at the moment is, we have ornamental grasses that don't seem to want to grow.

They were a green-blue colour

and now they've turned out to be a grey colour and just look dead.

They start off really healthy,

then they start to deteriorate, they start to shrink,

they start to get brittle and horrible

and they just end up like this, with clumps coming out.

We don't know what to do. We've tried all sorts of feed and spoke to different people

and it just doesn't seem to help at all.

Don't you think this would be just ideal for Lance and Suzanne?

-It's blue moor grass, isn't it?

-Yes, I think it's absolutely lovely.

It's beautifully erect, it's got a lovely purple tinge.

And it lives on the moors, so it'd be ideal in Darwin.

I mean, that festuca would make a good wig, but...!

We have real problems with the festuca.

We have given up on growing that

because it doesn't like the conditions here.

We're far too exposed and we're quite wet here, too,

so, no, this is absolutely perfect for what they want.

-Right plant, right place, yeah?

-Yeah.

That molinia provides so much texture and structure, doesn't it?

But they could do with colour too. How about that?

It's amazing, isn't it? It actually looks like it's on fire.

Crocosmias are unbeatable at this time of year, aren't they?

And that orange one just looks so brilliant.

That's ordinary montbretia, isn't it, coming through this blue geranium.

-Which one is it?

-It's Rozanne - "Gerwat" -

but it's an amazing blue, isn't it?

And it'd be perfect in that sort of place, too,

because it scrambles. It could come down the front of the wall.

It's working its way through the crocosmia, the montbretia,

really delivering on colour, particularly in this environment,

in challenging conditions.

You probably wouldn't find it anywhere else on a plant at this time of year.

I think there are a few ideas there, don't you, for Lance and Suzanne.

But I tell you what, they couldn't do better than risking coming over the border and taking a look themselves.

Well, they'd be more than welcome here any time.

People come to gardens like this for inspiration

and to answer all sorts of questions.

We've had an e-mail from Christine in Bradford.

This is my mum and dad's garden.

They've passed on now, so we are selling the house,

and what I'd really like to do is take some cuttings

of some of the bushes and the plants that are here,

that Mum and Dad got such pleasure from.

In particular, there's this magnolia, "Stellata",

and there's also a wisteria.

I'd really like to know how to take cuttings,

the best way to plant them up

so that I can recreate some of the sights

that Mum and Dad used to see in their garden.

Well, Christine, I'd love to tell you to go ahead

and take cuttings of your wisteria and your magnolia right now,

but, A, it's very, very late in the year to try cuttings of those two

and B, they are both really difficult subjects to root.

But there is one method you can use - layering.

The trouble is, it takes time for these layers to put on roots,

so you'll have to have the co-operation of whoever is moving into the house.

So here on this little Magnolia stellata, I've got a suitable branch.

It's one that is nearly touching the ground, and which is quite flexible.

I'm going to slit the stem just a few inches along its length.

And I'm going to keep that open by taking a little piece of twig,

so that will always keep that cambium layer exposed

and that's the layer where those new roots are going to be formed.

And then I can make a little trench down here.

In the bottom of it, I want to put some grit.

Just right the way down through there.

Now, into the trench...

And I'm just going to secure it with a couple of tent pegs.

I think, as a final measure, I'm going to put this bamboo cane in.

And that means that this new tree, cos that's what it's going to become,

is going to stand up straight, rather than just lying along the ground.

That's it, Christine. It's going to take about a year to root,

but I really hope that you can have a try

and that it's successful, because it would be really lovely

to take a part of your parents' tree back into your own garden.

Well, there's no question that if you want to get into the rhythms of a garden, patience is a virtue.

Mind you, that doesn't stop us trying things out,

even if they don't always work.

However, most of us are quite limited with what we can do

by the size of our gardens or our facilities,

whereas here at Wisley, they can try almost anything.

And by coming here, we get the benefits of their experiments.

I've always wanted to grow vines at Longmeadow,

and here at Wisley they have a wonderful collection of dessert grapes grown indoors.

Rebecca Bevan is responsible for their cultivation

and maintenance and has agreed to show me around.

-Mmm. They're beautiful.

-Aren't they just? And in their prime.

Absolutely heavenly.

This sounds a very simple question, but I've never been really clear,

the difference between a dessert grape and a wine grape.

OK, well, there are lots of grapes that are dual purpose

but these dessert grapes

have been especially selected for their quality for eating,

so they've got thin skins, really good flavour, they reach a big size,

whereas wine grapes are often higher in acidity,

very thick-skinned, quite small.

You've only got one row against the window,

whereas outside, you would fit two more rows here.

We want the maximum amount of space to train the rod over the roof.

We have a big space in the middle

because good air circulation is really, really important.

Grapes under glass can get a bit prone to powdery mildew,

so it's all about opening up the vents, getting the air circulating.

I've seen grapes planted outside. Is that a viable thing to do,

to plant them outside and then train them inside?

Yes, absolutely. In fact, that has lots of advantages

because by being planted outside, it's getting all the rainfall,

it's getting endless root space,

but the important thing is that the rod inside is getting all the sun

and protection to bring it into growth and get the grapes to ripen.

And what sort of age are these plants?

These have been in six or seven years.

And what about the soil?

Is it a standard soil or have you carefully sorted it out?

This is our normal greenhouse border soil, so we have quite a light,

sandy, free-draining soil. We've improved it a lot.

And what we actually do every winter is scrape off the straw

and also the layer of mulch, and expose that.

That way, we're getting rid of all the red spider mite

and any bits of pest and disease that might be around.

We then put a fresh layer of mulch down over the top of the roots.

Now, the fruit are exceptionally big and uniform.

-That's not accidental, is it?

-It's not, no.

When the bunches are forming, we actually remove 50% of the grapes,

so we go through thinning out the bunch

so there is space for them to develop.

This is a bunch where we didn't do that

and you can see some of the grapes are really small and packed in.

That can lead to fungal problems.

Now, you can't tantalise me with this fruit dangling inches from my mouth

-without offering me one to taste.

-OK.

-Which one do you recommend?

-This one is "Muscat of Alexandria",

which is obviously a muscat grape.

Said to be one of the best flavour grapes.

Now, this is a vine that really needs a decent amount of sun.

I thought we were going to lose the whole lot. I'll drop it!

Can I take one?

How lovely, to hold a bunch like that.

Oh...

Heaven, really heavenly. Mmm.

It really is worth going to the trouble, just to have that.

That's special. It's a treat.

Now, we've had lots of letters about growing grapes

and I do hope that this has answered some of your queries.

And more answers now from Carol at Harlow Carr.

Up here at Harlow Carr, I'm trying,

with the help of the RHS experts, to answer some gardening queries

sent to us from people who garden in a similar climate.

I have a couple of viewers' queries for gardener Russell Watkins

about how they can keep their lawns looking as immaculate as these.

And it looks brilliant,

especially considering how many people walk all over it.

-Yeah.

-What's your secret?

Well, if I'm completely honest, we don't to a huge amount.

We try and keep it to the bare minimum, so in localised areas,

we'll do a bit of scarifying, a bit of aerating,

but other than that, we don't do a huge amount.

I suppose you've got everything going for you. You've got good soil,

obviously a smashing grass mixture,

and you're on the slope, so drainage isn't usually a problem.

No, certainly not in this area.

Some of our viewers have lawns that aren't in quite such good condition.

Jason from Blackburn has written to us

and told us that he's got worm casts on his lawn and he doesn't like it.

Actually, it's a really good sign of a healthy lawn.

It shows that you've got worms present,

which, in a way, are kind of naturally aerating the soil.

Think yourself lucky that you've got all those worms doing all that work!

We've had another query from Kerry Byres in Warrington,

who's got two small lawns that are in shade most of the time

because of the house, I think. And quite damp.

And she's having huge problems with liverwort.

It's sort of taken the place over and she's at her wits' end.

OK. Well, that is absolutely the perfect conditions that liverworts like to grow in.

If it becomes such a huge problem, it might be worth starting again

with a new lawn and then keeping up with a real good maintenance regime,

but also really sorting out the drainage

because that's key to the problem, really.

She could think about introducing paved areas, couldn't she?

-Absolutely.

-And grow some wonderful shade-loving plants

that'd just love to live there.

So, Russell, you look after flowerbeds and lawns and trees too.

And one of our viewers has got a particular problem with

a specific tree in their garden.

We planted a Robinia "Frisia" pseudoacacia about 16 years ago,

and it matured into a beautiful tree.

The leaves are almost luminous, and it was a very nice shape.

It was just beautiful to look at in the garden

until this problem set in.

A couple of years ago, the leaves started to die back,

branches started to die also, and drop off.

Whether it's a disease or just something that they do, we're not sure.

So we'd be very interested in the correct advice,

and try and save the tree.

Well, I think Jane and Joe have got a bit of a problem there, haven't they?

-It does look like it.

-Normally, you'd suggest that they

just cut off the offending boughs,

-but it's gone past that stage, hasn't it?

-I think so.

It's looking like it is a fungal problem.

How about this as an alternative?

This is exactly what I would suggest.

It's a perfect tree, really. It's got a very similar habit,

the same-coloured leaf.

-And this is a gleditsia.

-That's right. Gleditsia "Sunburst".

And you can see that in the colour of the new fresh foliage.

-Yes, they just sort of burst forward, don't they?

-Indeed.

I think the thing about trees is,

they get to become part of the family, don't they?

You see them year in, year out and watch them grow.

I mean, there are so many small trees they could choose.

-Oh, yeah, absolutely.

-It's always sad to lose a friend

-but on the other hand...

-It's always good to have a new plant.

Yeah, it is, isn't it?

Now, if you've got any questions, please contact us

and we'll see what we can do to help.

It's very distressing losing a beautiful tree,

but at least it is just one plant.

But if you find you've got box blight, as I have in my garden,

and lots of you have contacted me to say that you have, too,

then the possibilities for catastrophe

are staring you in the eye. Peter Smith in Hampshire

is facing that problem.

I suppose it was about 15 years ago,

we visited a lot of formal gardens and I thought...

I was really inspired by them,

so I set out to create a knot garden of my own.

But, unfortunately, in more recent years,

it been affected by blight, and I have to say,

it's pretty distressing

to know that actually, in the end, I fear I'm going to lose it.

Is there anything that I could do to try and save the garden?

Maybe, if not, is it possible that you could advise me

on other plants I could use to give me the same effect?

Well, I do think Peter's garden looks simply amazing,

so it would be a tragedy to lose it.

While I'm here at Wisley, I want to find out what they're doing

about controlling and stopping the spread of blight,

and what alternatives that they suggest that he might use.

Colin Crosbie is the curator here at Wisley

and he knows every square inch of the garden.

Now, Colin, do you have box blight here at Wisley?

We've had box blight in the garden.

We've had to remove areas of box hedging and dispose of it.

We've had it, we don't have it at the present moment.

And if you have it - say you removed it and disposed of it -

is it controllable? Can you contain its spread?

There is nothing that's available for the gardener at home

that can treat box blight, so if you've got it,

what we recommend is to lift it, remove it, dispose of it.

If you've got a mature plant and you've got a little bit coming out,

then cut that bit of branch out, clear up the leaves that are on the ground and, if you can,

re-soil it, but it's a long-term job to keep doing that.

That does seem to be a disaster,

particularly if you're someone like Peter,

where his whole garden was based around a beautiful knot he had made.

Is there anything else that we can use?

There's a lot of wonderful alternatives.

My favourite is the Japanese holly, Ilex crenata,

very similar in appearance to box. Small leaves, and can be trimmed.

And my other one I'd go for is yew hedging,

you know, Taxus baccata, the common yew, an evergreen hedge.

It can be trimmed. Absolutely wonderful.

So, what you're saying is, this is a disaster

-but maybe it's an opportunity?

-There are many opportunities.

It's a case of experimenting. There are other plants too.

You could use berberis, some of the small berberises, or euonymus.

So, yeah, experiment and have fun and don't be put off.

Now, even a garden like this,

which is devoted to horticultural excellence and perfect plants,

still is based upon everyday tiny gardening jobs.

And here are some things that you can be getting on with at home

this weekend that they're doing at Wisley now.

Now is a good time to prune bamboos.

Cut out any old, tired stems and this will keep the plant healthy

and stimulate new growth in spring.

Select the stems that have lost their leaves at the top

and cut them away right at the base with a sharp saw or loppers.

And to contain the bamboo's spread, fork around the base of the plant

to expose any underground runners and then cut them back, too.

As we move into autumn, the foliage on many alpine plants is dying back.

And as the moisture levels increase, it's really important

to remove this dead and dying material

from around the base of plants,

which will reduce the risk of botrytis, or rot.

Clearing away old plant material

will also improve air circulation through and around the plant.

Vine weevil larvae become active at this time of year

and can do a lot of damage to the roots of plants,

especially those growing in containers.

They can be controlled by nematodes,

which are microscopic worms that destroy the larvae from within.

Nematodes need moisture to be mobile

so pre-wetting the soil will give the best results.

Mix the contents of the packet with water as instructed

and pour onto the soil.

Of course, it's always good to get tips

and techniques from the experts,

but you also come to Wisley, or any of the RHS gardens, for inspiration, too.

And I love the long mixed borders

which are staggering in their scale but also the details.

There's always something you're going to find at any time of year

that you can take back home.

Now, if you want to come and visit Wisley or any of the RHS gardens,

you can get in for free on Friday October 5th.

That's a free Friday on October 5th.

I shall be back in my own garden next week,

and I hope you'll join me there. So, until next Friday, bye-bye.

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