Preparing for Summer
May has to be one of the loveliest of months with the magic of the late spring flowers, the unstoppable growth of perennials and an air of plenty and fullness throughout the garden. It is the time of wonderful ‘fillers’, many of which will have self-seeded, such as Forget-me-not (Myosotis), Honesty (Lunaria annua) and Grannies Bonnet (Aquilegia). However, gardeners need to be aware that it is also the time of the ‘weed’ encouraged by ideal growing conditions of moisture, light and warmth.
Forget-me-nots, Red Campion and Pink Purslane making a fine display in late April
As always choosing just five ‘May’ plants that I wouldn’t want to be without has not been easy but in the end I have gone for the following. From the bulbs I have cheated a little and opted for two to share the prize. I know that many gardeners would choose the Tulip but I get much more pleasure from Allium and Camassia. They both look wonderful pushing up through and above the surrounding planting, the Allium with its purple, balls of flower and Camassia with its spikes of blue, purple or white blooms. Not only that, they will both return for several years unlike many of the Tulips! I have also chosen two herbaceous plants, both of which have become much more popular recently. The first is the Geum (Avens) which only a few years ago was represented mainly by the yellow, ‘Lady Stratheden’ and the red, ‘Mrs Bradshaw’ but has now become a much larger genus with lots of new cultivars available in yellows, oranges, reds, copper-apricot and copper-pink colours. The open, five-petalled flowers and central boss of stamens are a real delight.
Camassia leichtlinii Geum ‘Totally Tangerine’
At a higher level in the mixed border the Thalictrum (Meadow Rue) makes a real statement with its attractive pinnate, often glaucous leaves which can be lobbed or toothed and almost fluffy, delicate flower heads in white, pink, purple and yellow. Each flower head consists of many, tiny, petalless flowers with petal-like sepals (the outer layer of the flower) and often numerous, showy stamens and pistils (the male and female parts at the centre of the flower). My shrub choice for May was my father’s favourite, the beautiful Lilac (Syringa) which is hard to beat for both colour and scent. The conical flower heads are made up of small, tubular, very fragrant flowers which may be white, pink, red to magenta, lilac or blue. My fifth choice from the trees is the Malus genus in general and the Crab Apple in particular. There is little better than apple blossom at this time of year- gardeners love it, the bees love it and, where our crab apple is concerned, so too do a pair of bullfinches which have been visiting daily through the second half of April! The flowers are usually shallow, cup-shaped and, as members of the rose family, are five-petalled although in some cultivars they may be semi-double or double. In bud many are red or dark pink but open to pale pink or white. There are lots of excellent cultivars including M. ‘Evereste’ (white flowers from red buds followed by red-flushed, orange-yellow fruits), M. floribunda (pale pink flowers from red buds followed by small, pea-like, yellow fruits and M. ‘Red Sentinel’ (white flowers followed by long-lasting, yellow-flushed red, later glossy, dark red fruits).
Syringa vulgaris ‘Rhum von Horstenstein’ Malus ‘Evereste’
Looking back through past May blogs I see that in 2021 I was writing the last of twelve blogs about plants in our own garden in West Wales and in 2022 the blog was the last of twelve which I wrote about the gardens at Aberglasney. These are still available on the Old Railway Line’s website under ‘news/blogs’, ‘show tags’ and ‘monthly guides’.
My main topic for May’s blog and talk on Saturday May 4th (‘May the fourth be with you’ for all Star Wars fans!) is ‘Preparing for Summer’ which is all about getting the right plants in place to give interest and colour in the garden all the way through the summer and into the first part of the autumn. Unsurprisingly this is a topic which I have covered before and here I will try to draw together the main ideas. Essentially the plants fall into one of two main groups- the summer, tender perennials which we tend to treat as annuals and the more permanent, hardy, herbaceous perennials which form the backbone of our beds and borders.
I dealt with the first group in some detail in the May 2023 blog on ‘Summer Pots and Baskets’ although, of course, these plants can also be used within beds and borders as their old name ‘Bedding Plants’ suggests. When planting in containers of any kind there are basically three choices/decisions to make- choosing the right container, using the right compost and finally selecting the plants to use. There is a vast array of containers on the market and their selection is really a matter of personal choice but they will all have one thing in common- lots of drainage holes. The plants I am about to talk about certainly need water to thrive but they do not like to be sat in waterlogged compost. Such compost should be fresh, good quality, peat-free and contain some fertiliser for the first weeks of growth. It may also contain some moisture retaining gel/crystals which is particularly useful for hanging baskets. These plants are happy to grow in our summers once the threat of frost has passed but they are not keen on our winters as they generally come from warmer parts of the world. For this reason, most are treated in this country as annuals, growing, flowering and finishing in one growing season although some can be over wintered inside and used in the following year or even years such as Pelargoniums. I tend to think of them as falling into three groups although there is a degree of overlap between them- the ‘larger, taller plants’ which give height and focal points either in containers or the ground, the ‘fillers’ which cover the ground or containers and produce lots of flower colour and the ‘trailers’ which are obviously most useful in pots, baskets and raised beds/borders. There are many ‘larger’ plants to choose from with the most popular ones probably being Pelargonium, Fuchsia, Osteospermum, Argyranthemum, Cosmos, Diascia and Nemesia as well as plants such as dwarf conifers and Cordyline for foliage and structure. For many gardeners the Pelargonium remains a firm favourite with its brightly coloured, showy flowers and patterned, sometimes scented, leaves. They come in four main forms- Zonal, Regal, Ivy-leaved or Trailing and Scented. Fuchsias are also highly valued by many for the equally showy but pendant blooms which are produced over a long period through the summer and into the autumn. They come in two main forms- Bush and Trailing, some of which are hardy in our climate, others requiring winter protection.
One of the many forms of Argyranthemum which will flower almost continuously from late spring
The ’filler’ group is made up of smaller plants which cover the compost/ground, produce lots of flower colour and have real impact especially when planted in groups. Again, there are lots to choose from including Petunia, Begonia, Impatiens (Busy Lizzie), Bidens, Lobelia and Verbena most of which come in either bush or trailing forms. For me Petunias are great choice with the larger flowered, older, bush forms now being joined by some excellent, smaller flowered trailing types such as ‘Surfinias’ and ‘Tumbelinas’. A similar plant which has become popular in the last few years is Calibrachoa, particularly the ‘Twilight Collection’, which have small, trumpet-shaped flowers in shades of red, blue and pink with contrasting gold stars in the centre of each bloom. Begonia is another reliable choice and comes in two main forms- Fibrous-rooted and Tuberous-rooted. The former tend to be smaller, more compact and bushy plants with many, small flowers in white, pink and red and either green or bronze, fleshy leaves. The tuberous ones are quite different with their larger flowers in more vibrant reds, oranges and yellows plus a more trailing habit. Begonia ‘Apricot Shades’ is particularly good with its large, 3-4” (8-10cm) blooms in eye-catching shades of orange and apricot often right through into October. Both Petunias and Begonias have another great advantage in that when spent the flowers fall away and therefore the plants require no dead heading!
The ’trailing’ group has been covered to some extent in both of the other two groups but there are also some trailing, foliage plants which can be very useful, particularly in hanging baskets, to soften the container and to provide a cooler, green foil for the colourful plants of the other two groups. Two such plants are trailing Ivies (Hedera) and the variegated ground Ivy, Glechoma hederacea ‘Variegata’.
It goes without saying that we expect a lot of all these plants- lots of flower colour over a long period- and for this reason they do need some help in terms of watering, feeding and house-keeping especially if grown in containers. In the height of summer containers may need watering every day and in the case of hanging baskets possibly even twice a day. Choosing a good quality compost, adding water-retaining gel crystals or even using an automatic watering system can all help with this task. With all this watering extra feeding after the first month or so is needed to keep the plants at their best either in the form of slow-release granules or liquid feeds once or twice a week with some form of seaweed-based fertiliser. In terms of house keeping containers and plants in beds/borders need to be kept weed free, dead headed if necessary and any damaged or diseased leaves, pests and diseases need to be spotted and dealt with before becoming a problem.
I move on now to the herbaceous perennial plants which we grow mainly in our beds and borders for summer colour but some of which can also be grown in containers for the patio. I looked at my particular favourites in detail in the July, August and September blogs of 2022. In July it was Dahlia, Penstemon and Salvia, for August Echinacea and Helenium and for September Japanese Anemones, Rudbeckia and Aster (Symphyotrichon). In the June 2023 blog I added two more to my list- Sedum and Phlox. These blogs are all still available on the Old Railway Line’s website under ‘news/blogs’, ‘show tags’ and ‘Monthly guides’. The June 2023 blog also went on to look at good summer shrubs, climbers and ornamental grasses. You won’t be surprised to hear that, of course, there are many other excellent plants to choose from all of which can add to the glory of the summer garden including Agapanthus, Alcea (Hollyhock), Aconitum (Monkshood), Campanula lactiflora, Canna, Cephaleria gigantea, Cosmos atrosanguineus, Crocosmia, Eupatorium purpureum (Joe Pye Weed), Gaura, Helianthus, Hemerocallis (Day Lily), Knautia macedonica, Kniphofia (Red Hot Poker), Liatris, Lilium, Lithrum salicaria (Purple Loosestrife), Lychnis coronaria (Rose Campion), Stoksia, Verbena bonariensis and Veronica prostrata and spicata.
A lovely Japanese Anemone- Anemone hupehensis ‘September Charm’ for late summer colour
I think it is probably true to say that we all have at least one area in our gardens which is in shade for at least part of the day. Some of these shady patches are due to man-made structures such as buildings, walls and fences while others are due to large plants such as shrubs and trees casting shade on the areas beneath and around them. Shade cast by man-made, vertical features tends to create areas of damp shade except perhaps at the base of the feature itself. Away from this the soil, unless the feature is south facing tends to retain more moisture than other areas of the garden due to reduced evaporation from the soil surface. For some plants this is an ideal situation and such ‘damp shade’ areas should be regarded as bonus rather than problem areas in my view. At ground level bulbs such as Snowdrop (Galanthus), Dog’s Tooth Violets (Erythronium) and Bluebells (Hyacinthoides non-scripta) are perfectly suited to these conditions. Many ferns also do well in damp shade such as Athyrium felix-femina (Lady Fern), Polystichum and Blechnum and can add a great deal in terms of foliage shape, texture and colour even in areas of deep shade. Flower colour comes from the quite large number of herbaceous perennials which favour damp, shady areas such as Ajuga (Bugle), Anemone nemerosa, Brunnera, Digitalis (Foxglove), Epimedium (Bishop’s Hat), Helleborus, Pulmonaria, Thalictrum and Tiarella. Height, structure and flower colour can also come from a number of shrubs which can thrive in these conditions such as Aucuba (Spotted Laurel), Hydrangea, Mahonia, Sarcococca (Christmas Box) and Viburnum. There are also some climbers and shrubs which can be treated as climbers which can successfully cover the structures creating the shade. The true climbers include ornamental Ivies (Hedera), Virginia Creeper (Parthenocissus) and my particular favourite the climbing Hydrangea, H. anomala subsp. petiolaris. This is especially good on even a north facing wall or fence with its cinnamon-coloured bark, attractive leaves and, in summer, white, lace-cap flower heads. Shrubs which can be treated as climbers include the winter-flowering Jasmine (Jasminium nudiflorum), Pyracantha, Euonymus fortunei ‘Silver Queen’ and the Silk-Tassel Bush (Garrya eliptica).
Shade created by large shrubs and trees can cause more of a problem as it is more likely to be ‘dry shade’. Large, established plants remove large quantities of water from the soil as part of their growth processes, plus when in full leaf their canopies prevent some of the rainfall from reaching the surface below. However, although these places are not easy situations for smaller plants to survive there are still some which can. Autumn, winter and spring flowering bulbous plants are particularly well adapted to these conditions as they grow and flower when the soil is still moist and before the leaf canopy above is full. After flowering they die down and lie dormant through the dry, shady summer and rely on their stored energy to power their new growth when conditions are next suitable. These include both types of hardy Cyclamen, C. hederifolium which flowers in the autumn and C. coum which flowers after Christmas in the late winter and early spring, Winter Aconites (Eranthus hyemale) as well as the already mentioned Snowdrops and Bluebells. Ferns which can tolerate drier conditions are another good choice and include Dryopteris filix-mas and Asplenium scolopendrum (Hart’s Tongue Fern). There are also some suitable evergreens and herbaceous perennials such as Bergenia (E), Epimedium (Bishop’s Hat (E), Euphorbia amygdaloides var. robbiae (E), Geranium macrorrhyzum (E) and phaeum (D), Helleborus foetidus (E) (the Stinking Hellebore- only the root ‘stinks’!), Iris foetidissima (E), Lamium (Dead Nettle)(D), Symphytum (D) (Comphrey) and Vinca (E). There are also a small number of shrubs which can do well in dry shade including Aucuba (Spotted Laurel), evergreen varieties of Euonymus including E. fortunei ‘Silver Queen’ and ‘Emerald Gaiety’ and Kerria japonica. All these plants grow best in these difficult conditions if they are given a good start by adding lots of organic matter at planting time and afterwards annually as a mulch as would happen naturally in a woodland situation. This together with a good watering at planting time helps them to get established and hopefully to flourish.
Some plants, particularly some well known indoor plants, can be propagated quite easily at this time of year and in the coming months from whole leaves or leaf sections with different plants requiring slightly different methods. For plants such as African Violets (Saintpaulia) and Gloxinias (Sinningia speciosa) cuttings consist of a single leaf and leaf stalk. As with all cuttings the material needs to be healthy, undamaged and fully grown. In the case of these two plants the leaf stalk is cut from the parent plant at its base and then reduced to around 3cm (inch and a quarter) below the leaf blade. Each leaf and stalk can then be placed individually into pots of compost (one part peat-free compost and one part sand, perlite or vermiculite) so that the bottom of the leaf blade touches the compost. After watering and labelling, each pot can be covered with a small cloche made from the base of a plastic drinks bottle and then placed in a warm, light place out of direct sunlight. Each leaf should produce several plantlets which when large enough to handle can be separated and potted up individually. Coleus plants are propagated in water from healthy cuttings about 10-15cm (4-6”) long cut just above a node. Each cutting is then shortened slightly by cutting just below the lowest leaf node and the lower leaves are removed to leave a clean stem with around 3-4 leaves at the top. Several stems can then be placed in a jar of water supported by a piece of wire netting with the water being topped up over the next few weeks as roots begin to develop. When the cuttings are well-rooted they can be carefully (these water roots are quite delicate) potted up into the compost mix. Cape Primroses (Streptocarpus), on the other hand, are propagated by taking half-leaf sections. A leaf is separated from the plant at its base and then divided in half by cutting out and removing the midrib section thus exposing the cut bases of the leaf veins. The cut leaf sections are the inserted into a seed tray in the usual compost mix into shallow trenches and firmed in so that the cut ends of the veins are in good contact with the compost. The tray is best kept in a warm, light place and covered with a plastic bag or propagator. Plantlets will develop from each of the cut vein ends and can be potted up individually when large enough to handle. For Begonia rex plants there is yet another technique although it is still based on a single, healthy and young leaf. The leaf will have several strong veins and on the underside of the leaf each of these veins can be cut across its whole thickness. The cut will be up to a centimetre across, cutting the vein and a little of the leaf on either side. The leaf is then placed, cut side down onto a seed tray filled with the compost mix and the veins lightly pinned to the compost to give good contact. The tray can then be placed in a propagator or plastic bag in a warm, light place out of direct sunlight until new plantlets at each of the cut veins have developed. When large enough these can be separated from the leaf and then potted on individually.
This is a good time of year to take Fuchsia cuttings using the ‘softwood stem cutting’ technique which we looked at in March of this year. Once the cutting has successfully ‘taken’ and been potted up it can then be grown on to produce either a ‘bush’ or a ‘standard’ shape. For bush Fuchsias, as soon as the lead shoot has developed three sets of leaves the shoot should be pinched out to stop it growing any further. This stimulates several new shoots to grow from the leaf nodes below. When these have developed two sets of leaves, they too should be pinched out and the process repeated until a really bushy plant is created. Each of the pinching stages increases the potential number of flowers but delays the time of flowering. To create a standard Fuchsia the lead shoot must be allowed to grow on and as it does to be tied to a cane in order to achieve a straight, vertical stem. Sets of leaves which develop along the stem need to be left on to help the growth of the stem but any shoots which grow from a set of leaves need to be pinched off to concentrate the plant’s energy on the growth and thickening of the stem. This process is repeated until the stem reaches the desired height. The recognised stem heights are:- ‘miniature standard’ less than 25cm (10”), ‘quarter standard’ 25-40cm (10-18”), ‘half standard’ 45-75cm (18-30”) and ‘full standard’ 75-107cm (30-42”). After this, three more sets of leaves are allowed to develop before the growing tip is finally pinched out. Following this the ‘bush’ method is used to create a bushy head. Once the head has filled out the leaves along the stem below will usually fall off, if not they can be carefully removed. A ‘full standard’ will take around 18 months and a ‘quarter’ or ‘miniature’ around 6 months.
That’s all for this month but don’t forget that I will be at the Old Railway Line for my monthly talk on Saturday 4th May when I will go through the main points of this blog and illustrate them with some of the many wonderful plants which the ORL has to offer. It will be at 10am in the Wild Bird room next to the Pet Department and as always is free to attend.
In June the blog and talk title is ‘Hot and Dry’, and I shall be looking at how our changing climate is, and in the future will be, affecting how we garden. This will include a section on good plants for a drier and warmer climate and ways to conserve and make the best use of the water we have. I will also choose my five ‘June’ plants that I wouldn’t want to be without- I wonder what yours would be?
Until then enjoy your garden at this very special time of year.
Keith.