The Garden in October 2020

As we leave a glorious September behind, apart from the last week or so!, and enter into the main part of autumn it is the time to admire the sometimes all too brief show of wonderful colours before the leaves start to fall and flowers finally begin to fade. As the days continue to shorten and night temperatures in particular begin to fall the growing season comes to an end. This is signalled in many deciduous trees, shrubs and climbers by their brilliant colour displays before they shed their leaves and enter their dormancy period. The timing and vibrancy of these displays varies from year to year depending on the weather but some plants can be relied upon every year to produce rich autumnal colour, mainly in the red/orange range but also with some yellows.

Of course it is all to do with the magic of nature but there is a little bit of science behind it! Basically the plants are conserving their energy and nutrients, especially chlorophyll, the really magic material which enables plants to do what we can’t ie. to make food from the light of the sun. These chemicals are broken down into simpler forms and are sent back down into the trunk, main branches and roots to be stored safely through the winter. When the green leaf pigment chlorophyll is withdrawn other colour pigments are revealed that produce the colours which are characteristic of autumn. Carotenes and Xanthephylls create the yellows while the reds and purples come from a mix of Anthocyanins plus any sugars which are lingering in the leaf. The best colours are generated with bright, sunny days and cold nights which is why the often overcast European autumns are not always as colourful as those for example in New England in North America. Ok that’s the science over, you can switch on again now!

I have to begin with the most striking of the autumn plants because of their size and that of course is the trees. Most trees will show some colour changes in their leaves at this time of year but some are truly striking and I list some below.

Larger Acers such as A. japonica ‘Osakasuki’ and A. rubrum– both brilliant reds

Amelanchier lamarkii (Snowy Mespilus)- reds and yellows

Cercidiphylum japonicum (Katsura Tree)- reds, oranges and yellows plus the fallen leaves smell of burnt sugar, some say chocolate, when crushed!

Liquidamber styraciflua, L. ‘Worplesdon’- reds, oranges and purples

Parrotia persica (Persian Ironwood)- yellows, oranges and red-purple

Prunus sargentii, P. ‘Royal Burgundy’ -oranges and reds

Rhus typhina (Stag’s Horn Sumach)- oranges and reds

Sorbus commixta (Rowan)- yellows, reds and purples

In addition to leaf colour trees can also provide autumn colour through their fruits which some even carry into the winter if the birds allow it! The best ones include:-

Crataegus (Hawthorn)- which I have to say seem to be full of berries this autumn

Ilex (Holly)- female and self-fertile varieties with mainly red but also some with yellow berries

Malus (Crab Apple)- eg M.’John Downie’ (Red, flushed orange), M. x robusta ‘Red Sentinal’ (Yellow maturing to bright red)

Sorbus (Rowan)- eg S. cashmiriana (White), S. commixta (Red), S. ‘Joseph Rock’ (Yellow) and S. ‘Pink Pagoda’ (Pink)

Given favourable conditions most deciduous shrubs and climbers will produce some colourful tints before their leaves are finally shed but some are more striking and reliable than others. The impact of a group of shrubs in autumn colour can be spectacular but even a single, well-selected and placed specimen can provide an eye-catching effect in any garden. Some of the best include:-

Acers- almost all of the smaller Japanese Maples- a mixture of yellows, oranges, reds and purple

Berberis thunbergii– reds and purples

Cercis canadensis  ‘Forest Pansy’- rich purple summer foliage turns into a mixture of reds, oranges and yellows

Cotinus (Smoke Bush) eg  C. coggygria ‘Royal Purple’- scarlet, C. ‘Flame’- orange/ red, C. ‘Grace’- brilliant, translucent red

Euonymus alatus (Winged Spindle)- crimson-pink

Fothergilla gardenia– red, orange and yellow

Hamamelis (Witch Hazel)- orange and yellow

Parthenocissus (Virginia Creeper)- bright red

Viburnum opulus– red

Vitus (Ornamental Vine) eg V. coignetiae– large, heart shaped leaves turn crimson and scarlet

Like trees some shrubs also carry colourful fruits in the autumn and some of the best are:-

Callicarpa bodinieri– a striking violet-purple

Cotoneaster– mainly reds but some yellows

Leycestaria formosa (Himalayan Honeysuckle, Pheasant Berry)-dark red-purple

Mahonia aquifolium– bloomy blue-black

Pyracantha (Firethorn)- red, orange or yellow

Sambucus  (Elder)- black

Symphoricarpus (Snowball Tree)- white or pink

Viburnum opulus– bright red

It is clear from all the above that autumn colour is dominated by the brilliant tints of dying leaves and the equally colourful effects of berries and other fruits. Not surprisingly as the growing season comes to an end few perennials and shrubs choose to flower at this time but those that do are all the more valued. They include:-

Aconitum carmichaelii (Monkshood), Anemone (Japanese) eg  A. x hybrida ‘September Charm’, A. ‘Honorine Jobert’, Aster now Symphyotrichum (Michaelmas Daisy), Cyclamen hederifolium, Colchicum (Naked Ladies), Fuchsia, Helianthus, Hydrangea (the flowers may be losing their colour but they are still attractive as they fade), Nerine bowdenii, Rudbeckia, Schizostylus coccinea (Kaffir Lily), Sedum eg ‘Spectabilis’, ‘Ruby Glow’ and ‘Autumn Joy’, Tricyrtis formosana (Toad Lily).

There are also some perennials with richly tinted autumn foliage including:-

Ceratostigma plumbaginoides, Euphorbia griffithii ‘Fireglow’, Geranium eg wlassovianum and macrorrhyzum, Osmunda regalis (Royal Fern).

Finally last but not least we must not forget the grasses some with both colourful leaves as well as  striking seed  heads including:-

Calamagrostis x acutifolia ‘Karl Foerster’- pinky-bronze seed heads turn a warm buff or pale brown

Imperata cylindrical ‘Rubra’- green leaves turning blood red from the tips down

Miscanthus sinensis ‘Malepartus’- silvery flower plumes and green leaves turning golden orange

Many of the above and more are used to great effect in the Upper Walled Garden at the well-known Aberglasney gardens just south of Llandeilo. Teresa and I were there at the end of September and as always were taken aback by the still colourful and exuberant displays. I have raved before about the beauty of Helianthus ‘Lemon Queen’ and at Aberglasney they have them in large numbers in association with the rich blue, hooded flowers of Aconitum (Monkshood)- I think A. carmichaelii ‘Arendsii’ but a word of warning contact with the foliage may irritate the skin and all parts of the plant are highly toxic if ingested! These groups of yellow and blue are interspersed with white Anemone and Phlox as well as two varieties of Eupatorium. Firstly Eupatorium purpureum (Joe Pye Weed) is coming to the end of its flowering period but its large pink-purple flower heads are still dramatic on such large plants (up to 6 feet, 2 metres). A second Eupatorium which now seems to be named Ageratina altissima ‘Chocolate’ is also a delight and growing to 3-4 feet (1 metre) is perhaps more suitable for more modest gardens. It has wonderful pink-purple foliage with clusters of small white flowers at this time in the year and provides a great foil for the other more colourful plants. For autumn colours from trees and shrubs, Aberglasney certainly has its fair share but another great garden for this is Hergest Croft near Kington. Both are well worth a visit in October, as well as at most other times of the year, and surely for our physical and mental well-being at this time can be considered as “necessary” journeys!

Of course if you are happier to stay nearer home there is still plenty to do in your own October garden and the full list is given as always in the blog archives. As for Teresa and I we will be concentrating on a few things to keep the garden looking good and ourselves active! Firstly the leaves which we will admire as long as they still on the trees or in colourful patches on the ground will eventually need collecting and removing. On lawns, which hopefully you dealt with in September (don’t worry if you didn’t scarify, aerate, top dress and feed then because these can all be done in October as well), layers of leaves will damage the grass by excluding light and air so they need to be raked up and removed. This actually scarifies the grass to some extent and therefore is one of those wonderful win-win situations! We also remove leaves from beds and borders which are covering other plants and also from the pond to keep the amount of decaying organic matter to a minimum. If you only have a few leaves to deal with they can be added to the compost heap but if you have large amounts please don’t waste them as they can be used to make your own leaf mould, something which you can’t buy in a garden centre, even one as good as the Old Railway Line! Leaf mould is a wonderful and free form of organic matter which can be used as a mulch, a soil conditioner or mixed with other materials to make your own potting compost, as I do each spring when making up my special bonsai mix. The time honoured method is to use four stakes and some chicken wire to make a large cage which should produce usable leaf mould in 18 months to 2 years- yes, gardeners do need to be patient sometimes! Most gardens these days either don’t have enough leaves or enough space for a sizeable leaf container and use another high-tech method- a black bin bag! We just fill as many bags as we can, mixing different types of leaves together and making sure that the leaves are moist. The bags are then sealed and some holes pierced with a fork to allow air in. Unlike in a compost heap or bin where bacteria break down the vegetable matter generating a lot of heat as it does so, leaves are broken down by fungi, hence the need for moisture. We then put the bags out of the way behind the shed and garage and forget about them until they are ready to use. Leaf mould good enough for mulching and adding to soil will usually be ready after one year but to make the best ‘stuff’ for potting compost usually takes a second year. Don’t be alarmed as the bags get smaller and smaller over time, this is perfectly normal and even small amounts of this ‘black gold’ can be very beneficial to the soil by adding some nutrients and vital trace elements, increasing water holding capacity, improving the soil structure and providing food for beneficial soil organisms.

October is also still a very good planting and moving month for many types of plant hence my blog on shrubs in mid-September and my next one on trees later this month. Spring bulbs can also be planted this month apart from Tulips which are best left until November when the soil is cooler.

Over the past months you may have been wondering why I haven’t mentioned Dahlias. The truth is that I find most of them a little too blousy for my taste although I do like the ‘Bishops’ group with their simpler flowers and purple-tinged leaves. However, if Dahlias are your choice then we are nearing the time when the tubers need to be lifted and stored. Having said that in milder districts and with well-drained soils many gardeners now leave the tubers in the ground, perhaps covered by a good layer of mulch, and in most years they survive and are just as good next year. As for other herbaceous perennials many people use October and November to cut them down as they finish flowering in order to ‘tidy’ the garden for the winter. We try to resist this urge to be too tidy in order to leave some shelter and food sources for garden creatures and to give some height and shape to the winter garden. As long as the stems are standing upright we tend to leave them until the new year and enjoy their outlines in the winter, particularly when they are covered in dew or frost.

As we move into October and November some gardeners’ thoughts turn to the topic of digging and for many in the past any areas of bare soil in the autumn or winter were as a matter of course dug over. These days there is much more debate about ‘to dig or not to dig’ which I will discuss in my November blog, so if you can leave the digging until after then you might be persuaded that you don’t need to do it at all!

Another October task which for some is a bit of a chore is cleaning out the greenhouse or conservatory. However unpleasant an idea this might seem I have to say that it is well worth the effort. Choose a pleasant, dry day when the plants can be safely put outside to make the cleaning process much easier. Firstly all the glass inside and out needs to be cleaned in order to allow in as much light as possible during the shorter and often duller days of winter. Then any staging needs to be scrubbed down using a mild disinfectant (I use very dilute Jeyes Fluid and some rubber gloves!). I then finish off by using a watering can to apply the same disinfectant to the gravel and paving slabs on the floor of the greenhouse just to make sure that I have dealt with all the ‘nasties’ that might be lurking in the nooks and crannies. By the time you have finished you and the greenhouse will smell a lot cleaner and the plants can be returned after leaving the door and windows open for a few hours. You might have noticed that the word ‘I’ has been used throughout as in our house this is definitely a ‘blue’ job!

To finish I am going to give a brief mention to the plants which are catching the eye in our garden as we begin October. At the risk of sounding boring I have to start with the wonderful Helianthus ‘Lemon Queen’. We have two plants and they have clearly enjoyed the warm, dry and sunny weather of most of September so that they still have over a hundred flowers each which, when the sun shines, are covered in bees. As I have said before these are large plants, over 6 feet (2 metres) high and as such they have rather swamped their too flimsy cane wigwams but have fortunately  survived the wind and rain at the end of September. Over the winter I am planning to build two wooden obelisks to support the plants better next year. Next to one of them is Rudbeckia ‘Goldsturm’ which is much more suitable for a smaller garden but is still showing over twenty flowers.

 Also nearby is Cirsium rivulare ‘Atropurpureum’ with its deep crimson, thistle-like flowers standing above large, deeply dissected leaves which in turn is just across from the pink Anemone ‘Serenade’ which has been in flower since late July.

In addition to these there are three contenders for the award for flowering continuously over a long period. The first is Scabious columbaria ‘Butterfly Blue’ with its lavender-blue flower heads much loved by bees as well as butterflies which started flowering in April or possibly even before and I am confident it will go on into November. Secondly in the gravel garden the lovely plant with a mouthful of a name, Erigeron karvinskianus ‘Profusion’ has been full of its small pink and white daisy flowers since the spring. Also in the gravel garden Persicaria affinis  with its upright spikes of pink flowers in different shades has been flowering for just as long. I will leave it to you to choose a winner!

As for annuals , we planted some Cosmos ‘Purity’ plants out at the end of May and one in particular in a sunny spot has produced masses of its pure white flowers with yellow centres which, particularly as the light fades, stands out at the far end of the garden.

On the patio the three stars are a yellow Bidens, a pink Argyranthemum which is full of flowers again after the first flush of flowers were dead headed in Late July/early August and a striking almost burnt orange Bidens which has just never stopped flowering since planting out in early June. The two Bidens are grouped with what I call our ‘Waterfall’ Maple which has been colouring up throughout August and September to reach its mixture of green, orange and red stage with the promise of more oranges and reds to come. If you need any persuasion to grow Acers for autumn colour then this plant will convince you!

I hope that the above has given you some ideas of new plants which you might like to add to your own October garden and a few tasks to keep you out of trouble during the next few weeks. My favourite garden trees blog will follow in mid-October and then we will be into November, possibly not a month to fill you with enthusiasm but I will do my best to find a few items of interest. Until then good gardening, good planting and good health.

Keith