Friday, 30 March 2012

Some like it hot, many aren't too fussy.

To follow on from my last post about efficient use of water in pots I wanted to give you a glimpse of the way I decide where to position which plants during the summer. These are just my opinions, based on a lot of trial and error (and in this space I can't provide a comprehensive guide) but they may be useful to those of you who are wondering how they are going to keep your potted plants happy in a difficult year. If you are a beginner at this please don't be afraid to try, and to make errors. You may marmalise a few plants along the way but if you observe them carefully and if necessary move them, there will be few fatalities...
Succulents with their feet under terracotta gravel can take the heat. July 2007.
A basket of dahlias by itself - you'll
need to keep an eye on it... Sept 2009
Where is your pot?
Pots on their own, in a hot, dry location such as our stock yard, are difficult, especially if they are raised up and exposed to more drying wind. Succulents and a good inch of gravel mulch are the answer.
Even in the relatively lush courtyard garden, a pot by itself with a plant that requires plenty of water (such as this Dahlia Gallery 'Rivera', left) must be near a path where you will see it regularly, so that you can pounce on it if it starts to wilt. Try to keep it in part shade.
June 2008. Conventional mixed
planting in a Ham House Urn in the
drive of the pottery. Watering cans
needed regularly.

Over exposure
The Ham House Urns in the drive may be on the northern side of the hedge but they are exposed to the drying wind and too far away to water regularly. 
Sept 2011. Succulents in Ham House Urn
in the drive of the pottery.
No watering necessary!

I have had success with mixed plantings there with much lugging of watering cans. In the last two years, however, I have simply filled the pots with succulents and left them to it. No watering at all from early June to October, when they were dismantled.

Aeonium arboreum 'Zwartkop' on top of the well
with Pelargonium 'Duke of Edinburgh' and
Cineraria maritima 'Cirrus' doing fine but
the Lobelia and Verbena are struggling.
Sept 2007

In an exposed position you can mix large succulents, especially aeoniums, with other plants such as pelargoniums, cordylines and phormiums which revel in large dollops of sunshine and are fine with occasional dryness.

Shady deals
Many bedding plants which are often recommended for hanging baskets are surprisingly intolerant of drying. Lobelia and Nemesia for instance, may not die immediately but they will soon sulk, stop producing flowers, and keel over earlier than necessary. Many bedding Verbena will be susceptible to powdery mildew if allowed to get too dry too. Give them good light, but shelter from the wind and the hottest sunshine of the day.

Agapanthus like a front row seat
for sunshine. I think this is 'Bluety'.
July 2007
As for the smallest pots - well, in sunny positions I only put succulents in them for high summer. That way most of them won't need watering at all. If you have a collection of smallish to medium pots it's best to favour plants labelled 'drought tolerant' because even in a shady position it is easy to forget them and let them dry out - at least these pots have the advantage of being dunkable. Just put them in a tub of water which comes half-way up their sides for an hour or so, but don't forget them and leave them to drown!

Bring me sunshine
As mentioned in the last post I group the pots together for maximum humidity/coolness, but something has to go in the front row. Apart from succulents I often choose Agapanthus  or Nerine for this role as they enjoy a good baking.

Astelia chathamica 'Silver Spear', Plumbago
auriculata, Convolvulus cneorum and
Convolvulus sabatius thriving in a south-
facing site and a big Wisley Gardener Pot
September 2009
Drought tolerant/sun-loving plants often have grey or blue foliage, the heat-stress avoidance techniques associated with this colour include waxy coating on the leaves or a layer of fine hairs. Luckily for us gardeners this makes a tasteful selection of foliage in a sunny spot pretty easy at the same time as being water-efficient. Try plants like Cerinthe major 'Purpurascens', Astelia chathamica 'Silver Spear', Elymus arenarius, Festuca glauca, Lavandula x christiana, Argyranthemum foeniculaceum, Dichondra micrantha 'Silver Falls', Convolvulus cneorum and Convolvulus sabatius.

...and only sunshine.
Of course many of the sun-lovers won't flower well in shade. Plumbago auriculata and the pelargoniums, for example, need good light to flower profusely. Convolvulus cneorum/sabatius, Osteospermum and Gazania  flowers will stay sullenly closed in deep shade, and don't even think about putting Ipomoea tricolor (Morning Glory) in shade. Of course that doesn't mean that the bases of these plants need to be exposed to sun, so you can crowd other plants in to shade the surface of the planting and minimise evaporation.

Ipomoea tricolor 'Heavenly Blue' with its head in the sun of the entrance to Whichford Pottery but its toes
under lots of other plants. July 2010
Nasturtiums (Tropaeolum majus) flower surprisingly well in shade. I have used them in indoor flower shows in Japan and they were unique in flourishing and flowering with NO natural light in a department store! They will cascade just as happily over the shady side of a large pot as over the sunny one, so this is something to bear in mind if you are trying to save water by keeping most of your pots in shadier locations than usual. Petunias will be all right in part shade, too, and Nicotiana.
Tropaeolum majus (nasturtium) on the northern side of the entrance arch. July 2009

Fuchsia 'Bornemann's Beste' flowering well in
deep shade by the staff room, petunias and
pelargoniums are managing too. Sept 2010
Some plants deserve to be popular
There are quite a few plants which will happily flower in shade. This year we are denied bedding busy lizzies (fine if you choose the colours carefully, don't be snobbish!) because of a plague of downy mildew, but I cherish my plants of their huge perennial cousin Impatiens sodenii, a fleshy giant with white flowers which reaches 5-6ft tall given the chance. There are lots of good begonias and beautiful fuchsias too - don't let the fashion police deter you - which will flower well in the shade.

Of course all your foliage plants can be stuffed into shady corners to save water - but beware of putting snail food, like hostas, close to walls, as hungry molluscs will abseil down, grateful that they don't have to crawl over rough terracotta for their supper.

Undeniable thirst
Some thirsty plants, especially those grown for fruit such as strawberries, tomatoes and blueberries, work best with some sun at least so it is worth sitting their pots in saucers to catch any water draining out. But if the forecasts are wrong and it rains a great deal only the blueberry will be happy with its feet constantly damp.

Think before you plant
I have a wide-ranging collection of plants, and I'm not about to chuck them out because watering will be more difficult this year. But I am going to think very carefully about where to put them. It may be that many of them will have to be be in shadier places than is ideal, so perhaps they will produce fewer flowers, but at least I'll still have them when/if our climate regains its sangfroid.
The Salvia leucantha and annual Lupinus 'Summer Spires' in these pots would produce more flowers
in a sunnier spot but still look pretty spectacular in a lightly shaded position and require less water.
September 2007


  1. Great post Harriet, and yours are never too long, always inspiring and informative. Looking forward to meeting you when we visit in May.

  2. Thank you for your kind comments Paula! See you in May!

  3. Don't know which photo I like best, it might be the nasturtiums - they look amazing.

    1. Thank you! I had terrible trouble choosing the pics for this blog because I love summer and wanted to include far too many...