Inspirational summer planting at Pensthorpe Park

I recently took a trip to Pensthorpe Natural Park, a place I’ve been wanting to visit for quite some time.  It’s not that I’m a closet twitcher and fancied a day birdwatching – the reason I wanted to trek to the depths of Norfolk was to see the Millennium Garden, an acre of gorgeous planting designed by renowned Dutch plantsman Piet Oudolf.

Pensthorpe Millennium Garden.JPG

This is a garden designed to look its best in midsummer and late summer, and I’m glad to say that even though I got there relatively early in its peak season, it was worth the trip.

The garden consists of large drifts of plants which create a fantastic tapestry of colour.  No shrubs, just grasses and perennials, so there won’t be much to see in late winter and spring, but in July, August, September and on into autumn, it’s really something.

Echinops Veitchs Blue.JPG

Stunning blue globe thistles Echinops Veitch’s Blue at the garden entrance

Sited next to one of the many lakes in the park, all the way round the garden I could hear the constant hum of insects and, as the paths wind through the borders (occasionally with planting in raised sections) it was a treat to see bees, butterflies and dragonflies up close.

Planting .JPG

I have to admit some of the colour combinations were a bit on the garish side!  They wouldn’t be something I’d recreate at home or for my clients (I don’t think), but somehow in that setting, and I think crucially, at that scale, they worked.

Helenium 'Rubinzwerg'.  A very colourful combination!

Phlox ‘Dusterlohe’ and Helenium ‘Rubinzwerg’. A very colourful combination!

Shocking pink Phlox and a deep orange red Helenium certainly wouldn’t be everyone’s cup of tea, but I thought they looked great (from a distance at any rate!) and really provided a vibrant splash of colour.

Astilbe 'Purpurlanze'

A splash of purple from Astilbe ‘Purpurlanze’ in the foreground

The soil at Pensthorpe is quite poor, and of course Norfolk is a very dry part of the UK, but the Millennium Garden is irrigated, so plants which you wouldn’t normally expect to thrive in that environment (for example Actaea, Lythrum, Monarda, Persicaria) were doing well side by side more drought tolerant plants such as Nepeta, Sedum and Origanum.


This type of naturalistic planting is all the rage at the moment, and there are many other gardens to visit where you can see other examples.  (Check out Gardens to visit in late summer & early autumn).

Although I’m ashamed to say I struggle to tell the difference between a Moorhen and a Coot, I did enjoy being surrounded by so many birds (whatever they were!!) as I wandered around the park.


I took a walk over to the Wildflower Meadow which although past its best visually, was literally humming with insect activity, and is an important habitat for dragonflies, butterflies and demoiselle damselflies.

Plants along the stream in the Wildlife Habitat Garden

Plants along the stream in the Wildlife Habitat Garden

Pensthorpe also has a Wildlife Habitat Garden which has been planted with species to attract insects and mammals. Running water and a variety of nesting boxes also help to make this a fantastic wildlife-friendly environment.  It’s a great place to pick up ideas – as well as a visual feast at this time of year.

Pensthorpe Natural Park


Picture credits:  Janet Bligh

Fabulous plants for August

Let’s face it, a lot of gardens start to get a bit boring in midsummer, so if you’re looking for colour and interest for August, here’s a small selection of my favourite plants.

Hydrangea arborescens ‘Annabelle’
I’m not sure why, but Hydrangeas often appear on my clients’ ‘Don’t Like’ lists.  Maybe it’s the old-fashioned image and big blowsy flowers that does it.  But even the most hardened Hydrangea haters seem to fall for the lovely ‘Annabelle’.

Hydrangea Annabelle credit  Firgrove Photographic

Hydrangea arborescens ‘Annabelle’

I guess it’s the classic green and white combination, and the sheer size of the flower heads that wins them over.  They certainly make a real statement (the plants can reach over 6’ in height and spread, and the flower heads can get to as much as 10” in diameter!).

In an ideal world this variety of Hydrangea wants to be planted in moist but well-drained soil, with sun or partial shade.  They will grow in drier situations but the growth won’t be as vigorous and the flower heads won’t be as enormous – but that can be an advantage as often their weight makes the supporting stems flop over.  Top tip (wherever you grow them) – make sure you put in adequate support for the plants at the start of the season – that way you’ll avoid the stems getting damaged later on, and you’ll get to enjoy the plant in all its glory.  The flowers fade to lime green and the dark green foliage turns yellow in autumn, so it’s a great plant for mid- and late-summer interest.

Perovskia atriplicifolia
Perovskia, commonly known as ‘Russian Sage’ is technically known as a sub-shrub, as it grows from a woody base. This is a plant that thrives in hot sunny borders with well-drained soil and it’s always a very welcome sight in midsummer which can be a difficult time to find colour in the garden – the early flowers are over and the later autumn flowering plants aren’t quite at their best yet.

Perovskia 'Blue Spire' at RHS Wisley Gardens

Perovskia ‘Blue Spire’ at RHS Wisley Gardens, Surrey

To succeed with Perovskia, you should prune plants in late spring when they are starting to put on growth, rather than cutting back in autumn. You’ll then be rewarded with upright silvery grey stems with fragrant leaves and lovely violet flowers in late summer.  The best known Perovskia is probably ‘Blue Spire’ which reaches 1m in height, but I also use ‘Little Spire’ which as the name suggests is a smaller variety, reaching 60-80cm in height as a rule. For maximum impact, grow them in groups.

Geranium Rozanne ‘Gerwat’
This is one of those really long-flowering perennials I seem to include in pretty much every garden I plant!  I’m always looking for reliable, great value plants and this particular hardy Geranium is invaluable.

Geranium 'Rozanne'

Geranium ‘Rozanne’

No kidding, it flowers from June to October or even into November, and there aren’t that many reliable plants that can offer that sort of flowering period!
It’s fast-growing and spreading (up to 1 metre wide), forming a wide clump of foliage which is great to smother weeds, and its large blue flowers are held on stems above the mound of leaves.  Fine in sun or some shade, not fussy about soil type and generally very easy to grow.   Hardly surprising Geranium Rozanne was named ‘Plant of the Centenary’ at the RHS Chelsea Flower Show 2013!

Lythrum salicaria ‘Robert’
This ‘loosestrife’ is another long-flowering perennial which provides a real splash of colour in midsummer, and will attract lots of insects in search of nectar, so it’s great if you’re interested in planting for wildlife.

Lythrum salicaria 'Robert'

Brilliant colour from Lythrum salicaria ‘Robert’

Flowering from July to September Lythrum ‘Robert’ has dense upright spikes of deep pink flowers and reaches about 75cm in height.  It will grow in some shade, but Lythrums do need a reasonable amount of moisture in the soil to thrive.  In fact most Lythrums are ideal for bog gardens and to grow as marginal plants next to water. ‘Robert’ though, is alleged to be more tolerant of slightly drier conditions than other Lythrums and I have grown it successfully in the garden above, which has fairly water-retentive soil but is far from being classed as boggy.

Lythrum Feuerkerze

Lythrum salicaria ‘Feuerkerze’ AGM

A slightly taller variety is the reliable Lythrum salicaria ‘Feuerkerze’ AGM (Award of Garden Merit from the RHS).  It gets to about 90cm high and about 45cm wide, so all in all a slightly larger variety than ‘Robert’.

Clematis viticella ‘Venosa Violacea’ AGM
This is a very easy two tone purple Clematis which will tolerate some shade and isn’t too fussy about soil conditions.  Flowering from July to September and reaching up to about 3 metres in height, it’s great to climb up trees and scramble through shrubs which have finished flowering and could do with a bit of extra colour at this time of year.

Clematis venosa 'Violacea' AGM

Clematis venosa ‘Violacea’ AGM

It’s not so big that it will get out of control and is such a good plant it’s been awarded the RHS Award of Garden Merit.

Eryngium giganteum ‘Silver Ghost’ AGM
Eryngium (or ‘sea hollies’) are great plants for dry sunny gardens with poor soil, where they will thrive.

Eryngium Silver Ghost, Perovskia, Echinacea

Great planting combinations at RHS Wisley – Eryngium ‘Silver Ghost, Perovskia and Echinacea

They look fantastic with grasses and plants like Lavender, Perovskia and Nepeta which like similar conditions.  But they are not only valuable for the fact that they will grow where many other plants won’t, but because they offer such a long season of interest, having a beautiful architectural form which lasts long in to the winter.  There are many varieties of Eryngium, and ‘Silver Ghost’ is a biennial (which means it flowers in its second year and then dies after setting seed).  The flowers turn blue as they mature and can be dried for flower arranging.

Eryngium 'Silver Ghost'

Eryngium ‘Silver Ghost’

Many other Eryngiums are perennial and it’s worth growing a mix of varieties for different flower forms, heights, and shades of blue and silver – if you have the right conditions in your garden.

Picture credits: Janet Bligh & Firgrove Photographic

Jobs for the productive garden in August

Get the most from your kitchen garden and cutting garden this month by keeping on top of your seasonal jobs

Keep up with cutting, feeding and/or deadheading on a regular basis.  Dahlias don’t open in the vase so only cut them when the flowers are open.

Angelica archangelica

Collect seeds as they start to ripen, and either sow them now or store them carefully to sow next year

Harvest plums & damsons as soon as they ripen to get to them before the wasps and birds do!

Lift and pot up, or re-plant any rooted strawberry runners which you want to keep as new plants for next year’s fruit.

Fruit trees – prune over vigorous growth on wall trained plums, cherries, apples and pears.  Cut our badly placed and weak shoots in order to encourage growth and reduce the risk of disease.


Remove old fruiting canes on loganberries and early fruiting raspberries, and tie in new growth.

Sow Oriental vegetables, spring cabbage, and salad onions. And keep sowing cut-and-come-again salad.

Sow green manures in empty beds in the kitchen garden. The crop can be dug into the soil in spring and will feed your soil. This is a great way to add nutrients and improve soil with the minimum of effort.  There’s a really useful video on the RHS website about how to do this.  Recommended viewing!

Contine  to pick courgettes, cucumbers and beans as this encourages further cropping.

Lift onions, shallots and garlic when the leaves turns yellow and papery.  If the leaves haven’t already bent over, do it yourself and leave the bulbs in the ground a little longer.


Harvest second earlies and main crop of potatoes when they start flowering.

Watch out for signs of Tomato & Potato Blight, which are common at this time of year.  If you’re not sure what the symptoms are, take a look at the RHS website which is full of very useful information on this and other pests and diseases.

Picture credits:  Janet Bligh & Firgrove Photographic

Jobs for the garden in August

There’s not too much to do in the garden maintenance-wise at this time of year, but it’s important to keep up with deadheading, watering and feeding to ensure as much flowering as possible for the rest of the summer.  Here’s a short list of other jobs to keep you occupied this month:

Give hedges (both deciduous and evergreen) a final trim for the year over the next few weeks.  Conifer hedges can suffer from dieback if they are cut back too late.

Clipping hedges

Trim back long growth on Pyracantha shrubs & hedges (without taking off the new winter berries which will be forming now).

When they have finished flowering, clip the flowers off Lavender and Santolina.  Lightly trim the plants to keep them compact & tidy, but don’t cut back into old wood (the stem below the foliage growth).  You can also tidy up Rosemary bushes now.

If you would like to save Lavender for drying, cut it now while it’s still flowering.  Tie stems in small bundles and hang them upside down in a dark well-ventilated room to dry.


Feed Camellias and Rhododendrons with a high potash fertiliser to encourage more flower buds next year.

Thin & shorten rambling roses, and cut a third of stems at the base to encourage fresh new growth.

Continue deadheading flowering perennials as long as possible (plants which really benefit from deadheading include Knautia, Anthemis, Helenium, Scabiosa, and Salvia).  Cut off flowered heads with secateurs, snipping the stems as low as possible to avoid leaving unsightly stubs.

Cut back hardy geraniums and other perennials which have finished flowering and are looking tatty.  Leave plants which have attractive seedheads and stems for winter interest.

Plant autumn flowering bulbs such as Nerine and Colchicum.


wildflower meadow
If you have a summer meadow which is over, now is the time to cut it – when flowering is over and seed heads are ripe

Sow lawn seed from late August.

Clear out decomposing leaves and thin out oxygenating plants.  Keep an eye on water levels and top up as necessary.

Keep feeding your containers with high potassium for prolonged flowering.

Collect and store the seeds of hardy annuals and perennials you may want to sow next spring.

NB this information applies to gardens in the UK and of course, you need to take account of your own local weather conditions when carrying out any work in the garden.

Picture credits:  Janet Bligh & Firgrove Photographic