Category Archives: Horticultural advice

Lobelia perennials

Lobelia – but not as you know it

Lobelia is most often seen as the little semi-trailing blue, white and purple plants that are used as frothy little annuals in borders and hanging baskets.

There are perennial lobelia too and I prefer them. I’m concentrating on Lobelia speciosa; there are just over 30 varieties of them, all of which are in the deep pink, scarlet, purple colour spectrum. Some varieties are very unusual. The most popular is probably ‘Russian Princess’ which has reddish leaves and bright scarlet flowers.

Lobelia perennial

We grow a number of varieties which are clump forming, generally getting up to about three feet high (or a metre in new money) so make sure you have the room as they won’t fit in many baskets!

They like a fertile soil that is moist but not waterlogged, and they are often planted by ponds. We keep ours in the Walled Garden, which, like the rest of Dartmoor, is reliably moist. If you have full sun or partial shade that will be fine. They aren’t too fussy but as bees love them and they are very brightly coloured I try to plant them in a sunny spot. We use plant supports in our borders so they are secured against the wind. If you leave them unsupported they should be fine but can flop a bit in very windy or wet weather. As a rule of thumb, they should be OK unsupported but pop some supports around the clump if it’s likely to flop onto a path or a lawn.

If you grow lobelia from seed you’ll find it is very fine so you’ll get a clump of seedlings to carefully prick out. Just keep the soil moist and warm until germination. I’d water from the base as the seedlings are very delicate until they get a bit more established.

With the established plants we have I divide them in spring to make new clumps, so once you have either bought a plant or grown some from seed you should have a good source of these super plants for years to come.

Happy gardening.

Nick.

Agapanthus advice

Colours of the sea and sky

In the Summer Garden right now we have repeats of this deep blue agapanthus in full flower, and every day I hear people talking about it. We’ve placed them amongst grasses and alongside bright yellow achillea, so it stands out a mile. This deep, dark blue is one of the more unusual varieties. Agapanthus are more often a lighter blue or white. They don’t come in anything on the red spectrum.

Agapanthus are summer bulbs from South Africa and they will make a big impact in your borders or in containers. They aren’t cheap; (I saw two bulbs in a 20cm pot for £8 the other day), but they will last for many years so they are good value in the long run.

Agapanthus Navy Blue at The Garden House, Devon in August

I keep seeing them outside snazzy beach-themed holiday properties, and they have come to be an architectural flower of summer; a flowering version of a bay tree in a pot by the door. It makes sense as they are the colour of sea and sky and they work well on their own or companion planted with a variety of colours and forms – whatever takes your fancy.

They like a good soil and don’t like sitting in wet, so whether you plant them out, or in containers, incorporate grit if drainage is poor. Oh, and don’t bother with them if you only have a shaded space – they need full sun. They give interest for a long period as they go from leaves to flower to seed heads over many months. You can get evergreen varieties too for even longer interest, but they are less frost hardy than the decidiuous ones.

If you grow yours in pots, keep the pot snug to the root ball. They give better flowers when their root ball is constricted. Ours are in the ground where they form clumps and generally get on well. They are frost hardy and I don’t worry about lifting them at all. Flowering is decreased the next year if the bulbs dry out completely for a long time in the autumn. But there’s not much chance of that here on Dartmoor!

Happy gardening.

Nick Haworth, Head Gardener

Irises all around the garden

Siberica, Germanica, Pacific Hybrids – all welcome here

This month I’m going to talk about Irises as I’ve been thinking about just how valuable they are in the garden.

They are versatile, colourful plants and I’m happy to have plenty in various conditions. They bear bright flowers on slender stems so they’re very handy for anyone planting a border; you can have them drawing attention at different heights without using too much space at ground level. The detail within the flowers can be stunning, with fine veining, marbling and contrasting colours.

Iris siberica ‘Weisse Etagen’ in the walled garden

I’ll begin in the wet with the sibericas. These irises are all shades of blue, usually planted in pond margins. I use them in borders too, as long as they have reasonable soil they will be fine. In one bed I’ve got them with the pink geranium, ‘Rozanne’ and the colour makes me smile every time I see it. If you enjoy pink / purple / blue this combination is well worth a try.

Irises are stately plants that can be used as part of a carefully designed border or drifted through more ‘natural’ planting schemes. There really is one for every place in the garden. If your soil is well drained and sun-baked, germanicas are the species to look for. These are the ‘bearded’ Iris that grow to about 1m tall and need their rhizomes baked hard each summer. I’ve just planted ‘Kent Pride’ which has a striking peach and yellow flower. I’m looking forward to seeing it flowering next year.

The choice of colour is almost endless, especially as the Pacific Hybrids are being cultivated. This group of plants derives from cross-breeding between 11 different types of Iris, and they are extending the choices for planting colours, situations and combinations. I have these on woodland edges and shady borders as I’m experimenting with how far I can get them to adapt to all corners of our Dartmoor valley. I’ll keep you posted with the results.

Nick Haworth, Head Gardener, The Garden House

May plant Iris where she don’t belong

Right plant wrong place! Moraea huttonii

Well, as we’ve had one of the best behaved springs I can remember, and we have plants all ahead of themselves, I thought I would keep the optimism going and feature a plant that behaves better for me than all the descriptions suggest.
It’s name doesn’t trip off the tongue too easily; Morraea huttonii is a bit of a mouthful for a plant that most of us would describe as a yellow Iris.

Moraea huttonii a yellow Iris

Moraea huttonii at The Garden House, Devon

It’s a super plant that I use down through the summer garden to lead the eye all along the planting scheme. At 1 metre high it gets your attention and the vivid yellow flowers really stand out amongst some quite lofty grasses and colourful perennials.

If I believed the plant dictionary description I wouldn’t plant it though. It should be in a sunny, south or westerly position, on sand or loam so the corms; (rhizomes if you prefer) bake in heat, stay on the dry side and never sit in water. It should avoid wet winters and frosts and if it’s really cold I should have it in a greenhouse.

Poor Iris – but it does well

Well, I keep it on a slope that faces east and tips north. It’s often sat like an island in the stream in winter as the rain comes in torrents, and as if that wasn’t enough it’s planted in shale. About the only thing that’s working for it is that here on Dartmoor we’re on acid soil.
I never lift it in the winter, so it doesnt get the dry, dormant period its supposed to need. Each year the corms are raised and split after flowers have faded, which is the best way to propagate in the Iris family.

Worth taking a risk for a plant that suits your garden design

This lovely Iris is a perfect example of how sometimes it’s worth taking a risk with a plant that just feels like it’s right for the effect you need. It’s too easy to buy a plant on impulse and then keep it in a pot because you don’t have perfect conditions and you don’t know where to put it. I say get it in the ground and give it a chance. Just like the weather, any plant can surprise you and leave you smiling. Right plant, wrong place can sometimes work. Now I just need to get out in the garden and start doing a sundance!

Enjoy May  – it’s certainly off to a fine start.

Nick Haworth, Head Gardener

Arisarum proboscideum…mouse mats!

An unusual plant for April & May

We’re spoilt for choice in the garden now so I decided to look around for plants that are a bit different to the run-of- the-mill spring blooms. Take the Arisarum proboscideum for instance. It’s a great little plant with a long Latin name and a fun common name. Mouse plant. It gets its mousey-moniker because the protective cover over the flower extends to a long tip that looks like a mouse tail. It looks as though a little brown mouse has just dived for cover headfirst into each flower.

A small plant that looks like a mouse

Arisarum proboscideum

Apart from being a conversation starter, these perennial plants are easy to grow. The little rhizomes spread to form a mat (a mouse mat?!) of dark green, heart- shaped glossy leaves, before the flowers appear for April. It will spread happily in shady spots of good, moist soil. I wouldn’t say it’s an invasive plant, but like real mice, it will make itself at home if conditions are perfect, so keep an eye on it.

It grows low to the ground, about 15cm high. It’s a good idea to plant it where you can see it and enjoy the quirkiness. It’s in the Araceae family, so it’s related to the arum lilly. The small white flowers have that similar sort of funnel shape, although they tuck over rather than stand upright. It’s definitely the unusual form ‘mouse tail’ that makes it special.

Arisarum is a woodlander, and fully hardy, so it will survive a tough winter, whether it’s cold or wet or both. You can propagate it from seed, or increase numbers by digging it up and dividing it in the autumn or winter.

i’m very happy to have this plant in the garden and it’s an excellent choice whether you are a novice gardener looking for something that you can’t break, or an experienced gardener wanting to have something unusual growing in the spring.

Happy gardening!

Nick

The Marsh-uns are coming

What to see in the garden in March

When I was thinking about what plant to feature this month I found myself listing the virtues of the Caltha palustris – or marsh marigold as; ‘easy to keep, wildlife attractors, good colour, virtually indestructible.’
All of which makes me feel very confident in recommending this native pond plant to any gardener with a patch of boggy ground or waterside planting place. Here on Dartmoor we’ve no shortage of wet ground to make these tough plants feel at home!
Marsh marigolds splash patches of bright yellow clumps around the lake and at the sides of our streams from mid-March for a month or so. They die back by summer and emerge again proudly to their 50cm height next spring. I enjoy seeing their bright green, heart-shaped leaves emerge, before the vivid flowers open.
They are in the buttercup family and although they have rhizomes they’ll spread by seed if left alone. They look very similar to buttercups with their yellow cupped single flowers but unlike their common cousins, they don’t spread vigorously or invasively.

Cows hate them, bees love them. I tend to garden for bees more than cows so I’m not bothered by their nasty taste. Early in the year they are a great source of food for wildlife and a welcome sign for gardeners that the season is stepping up a gear.
As long as their roots can stay wet they will be happy in any soil, or popped at the edge of a pond in an inch or two of water. They will do best in full sun, but don’t mind part shade. Hopefully you are getting the picture that if you keep them wet they are a very rewarding plant. If you have a small space, a plant or two will give splashes of bright colour. If you let them spread down the side of a stream or in a damp gully you will enjoy bold, bright springs for years to come.

Winter iris

Winter iris bring a touch of blue

The early spring bulb meadow is an area of the garden that I keep coming back to. Early flowering bulbs tend to be low to the ground as they are hardy enough to cope with lingering, rough weather. When I crouch down to look at the early iris and crocus bulbs in February and March they are a blast of colour and fascinating detail. Stand up and look down on them and they can look a bit humble before they really get going.
I haven’t got time to spend all day crouching, so the solution is to look at where they have come from, and plant them in a similar way.

Iris histrioides  ‘Angel’s Tears’

Iris histrioides ‘Angel’s Tears’

Iris histrioides – the winter iris

Take Iris histrioides, commonly known as ‘winter iris’. It’s typically a vivid blue iris in various shades. In Turkey, where they grow in the wild, they burst through the ground on naked stems and turn mountainsides blue. Inspired by this I’m planting more and more bulbs for early spring, so that in years to come we will have our own carpet of colour.
Some of the iris varieties here are unusual, so bulbs are expensive or impossible to find in bulk. That’s why I’m letting mine bulk up their numbers naturally, whilst under-planting with the easy-to-find Crocus tommasinianus. The light mauve of the crocus and deeper blue of the iris work perfectly together. I’m looking forward to the days when they have naturalised so abundantly that we need to thin them out.

I can’t recommend winter irises strongly enough. Look out for the readily available Iris reticulata in the garden centres or online. There will be a number of varieties to choose from. Plant them in the autumn a couple of inches deep and look forward to the day in February when they push up and turn out blue.

You don’t need a bulb meadow or mountainside to enjoy the power of these irises. They are perfect for well-planned pots partnered with violas or winter pansies. They also make an impact in small areas where their colour will pack a punch. Just make sure the drainage is good. They are pretty tough, even pushing their way through snow and ice. Get your camera ready for that; it makes a change from snowdrops!

Nick Haworth, Head Gardener

January – delightful Daphnes

Daphne scents – a Christmas present

Daphne

One of the joys of being a gardener is sharing experiences in the garden. However, the garden is closed through the winter, so special moments can pass by unnoticed.
Right now if I could share one thing with you it would be the scent of a Daphne growing near the path by the arboretum. It’s a non-descript shrub for most of the year, an evergreen column, head-height, with narrow, glossy leaves. Thousands of people walk past it, eyes drawn to more dramatic views. However, this Christmas, a present all for me was the scent of the Daphne, drifting in a mild breeze.  Dartmoor is nowhere near as high as the Himalayas, where Daphnes, also called ‘Nepalese Paper Plant’ herald from. Imagine the knock-out scent of a host of these plants on a high mountain breeze!
You don’t need much space to grow one. Daphnes vary from small bushes at almost ground level, to 2m shrubs. There are a number of varieties. The one I am describing is Daphne ‘bholua’. I think they are relatively expensive to other shrubs, but I forgive them as winter perfume is worth a few extra pounds.
If you can, invest in a taller plant to enjoy scent at nose-height. You’ll need a sheltered spot, but don’t get hung up on that – just avoid wild and windswept! They tolerate most soils; moist and well drained is best, sandy and exposed would be worst. Part shade suits them better than drying out in full sun.
They are easy to look after, very hardy and slow to grow. Bear that in mind as its worth buying the biggest plant you can. Spring planting is best, so your Daphne can get established for a winter display.
I wouldn’t be without one in any garden that has winter interest. And frankly, this Christmas, it was the best present I had!

Nick Haworth, Head Gardener

October plant of the month – Abutilon

How to grow Abutilon

Abutilon

Tropical-looking Abutilon flowers in October

Our mild climate makes it possible to grow semi-hardy plants outside and be rewarded with some pretty exotic looking plants late in the season. In October there are plants either popping up as autumn bulbs or surprising us with long flowering displays. Abutilon are long-flowering Brazilian medal-winners in an autumn planting scheme. They belong to the genus of mallow plants, (Malvaceae) with an exotic look and bright colours, often golds, pinks and reds.

Abutilon ‘Victory’

Abutilon ‘Victory’ is a trailing variety, reaching up to 2m high. It’s happy outside as long it’s protected from frosts below 5 degrees. I haven’t lost one yet and as I garden on the edge of Dartmoor don’t worry about it being tender.

It’s semi-evergreen, losing leaves as new ones push through. Let it stand free as a trailing shrub, or tie it like a short climber. A wall can provide shelter from frost and support, but it might starve the roots from moisture and that’s no good for this tropical, greedy-feeder. Make sure you keep it well watered and fed.

As the days shorten you want to keep the flowering going for as long as possible, so think about the passage of the sun through your garden and position it for as many hours of sunshine as you can.

Prune if you must in late spring, when you can also take softwood cuttings for back-up plants in case we get a really hard winter that catches us all out.

I enjoy the colour this plant brings to the garden. I dot them where the colours can be seen at head height to appreciate the contrast between the gold and red flowers. They work well on the terraces so visitors experience them at different heights. I think there’s a lot to be said for looking at the detail of October plants. The big sweeping drifts of summer colour may be gone but there is still plenty to enjoy in the garden.

Nick Haworth, Head Gardener

September plant of the month – Actaea

How to grow Actaea

The Actaea pictured is ‘Black negligee’; a thigh-high plant with frilly-flowered spikes of tiny white-to-pink flowers. It earns its name from the dark, deeply bisected leaves that suggest a lace pattern around the edges.

Actaea simplex 'Black Negligee' a spike of white flowers above black foliage

Actaea is a valuable September plant in the border.

Actaeas are perennial, and a good choice for herbaceous borders. Plant them in good garden soil and mulch or feed at least once a year. They are forgiving plants as they don’t mind wet soil and they aren’t fussy about acid or alkaline. Try to give them some shelter and they will grow to a couple of feet wide and over a metre tall. If all you can offer them is an exposed, windswept site with poor soil – don’t bother. They may be forgiving, but there is a limit to their generosity!

September flowers with plenty of early morning and evening scent

They flower in September, so plant yours somewhere where you can loiter in early morning to enjoy the sweet, exotic fragrance. Maybe you will enjoy your ‘Black Negligee’ while you garden in your pyjamas!

Actaea spread by extending their rhizomes – flat fingers of rooty bulbs. They are not invasive and the rhizomes are handy as you will like as not want to divide them to create more plants in early spring. It’s easier than growing them from seed.

If you have enough room plant a few to form a dark wall of foliage, under spires of flowers that can reach waist height with a scent that will catch on the breeze and attract pollinating insects.

There are plenty of varieties to choose from; almost all have the dark foliage that I prefer. Actaea is a favourite of mine as the leaves are a perfect backdrop to pretty much any brightly coloured flower whilst the flowering spikes are worth attention in their own right. I have planted them in our long borders, fronted by bright pink dahlias, yellow fennel and a variety of other “hot” and purple flowers.

Nick Haworth – Head Gardener