The May Garden 2023

Well weather-wise April has certainly given us a bit of everything as it so often does. Hopefully May will be less variable and plants as well as gardeners can look forward to some good growing conditions which will transform our gardens with the spring flowers in glorious bloom and trees and shrubs coming into full leaf.

In our own garden in West Wales May sees the cherry blossom giving way to that of the crab apple, the pond really coming back to life for both plants and aquatic creatures (the newts are particularly active at the moment!), the Honesty, Lunaria annua, gracing the borders, most of them with white flowers this year for some reason, the lawn greening up nicely and looking more like grass than moss, the lilac, Syringa, full of flower buds and promising much for later in the month and into June and the birds doing what birds do in the spring- nest building, egg laying and generally being very busy around the garden.

My main topic for this month and for my talk on Saturday April 29^th (we moved it forward a week so as not to clash with the Coronation) is ‘Summer Pots and Baskets’. Coincidentally in May 2020 I wrote a blog on planting in containers in general in which I covered some of the reasons for using containers, the types available, possible composts to use and the care and attention which they require. In May 2021 the blog came from our own garden and included photographs and details of some really good plants for the late spring and the May2022 blog was my last from the wonderful Aberglasney garden and is full of photographs of yet more beautiful plants.

The main jobs for May are mentioned in most, if not all, of them and for us they include protecting tender plants from low overnight temperatures when necessary, hardening-off young plants ready for planting out when the danger of frost has passed, getting on top of any weeds with fingers, trowel and hoe, keeping an eye open for the first signs of any pests and diseases, cutting the lawn but not too low at this time of year, sowing and planting up the vegetable beds, planting up the tomato growbags in the greenhouse and starting to water when and where necessary using water from the butts.

Growing summer flowers in pots and baskets requires the gardener to make three main decisions- a choice of container, a choice of compost and a choice of plants. As far as containers are concerned there is now a vast array of different styles, shapes, sizes and materials to choose from although in practical terms any sort of container that can hold compost and has some form of drainage hole or holes will do. Some of these might be considered a little quirky such as old gardening boots, tyres, toilet pans, kitchen sinks and old chimney pots but the more middle of the road choices also come in great variety from pots, troughs, window boxes and of course hanging baskets. These come in a wide range of materials each of which have their own advantages and disadvantages. Taking pots and troughs first probably the most traditional material is terracotta which is essentially baked clay. These are available in a wide range of shapes and sizes, look very natural when weathered and allow the compost and plants in them to breathe as they are porous. However, although many terracotta pots are relatively cheap they are not all frost proof or even frost resistant as they have not been fired to a high enough temperature. If terracotta pots are your choice and they are to be used throughout the year and not just in the summer it is definitely worth paying a bit more for a ‘British pot’ which will have been fired to a high temperature. In recent years plastic pots and troughs have become much more popular with gardeners due to low cost and the ease of moving and cleaning. However, they will always look like plastic and can become brittle with age. Wood has been popular over the years as a more natural product and particularly in the form of half barrels is a good way of having a large pot for trees and shrubs at a reasonable price. However, wood will eventually rot even if treated on a regular basis and once filled large wooden containers are very difficult to move. Other types of man-made pot are those made from reconstituted stone ie. concrete. These weather in time to give a more natural look but like wooden barrels are on the heavy side. Finally in recent years the ceramic pot has become very popular mainly I think because of their reasonably low cost and the great range of colours, sizes and shapes in which they come. They can become heavy when filled depending on their size but because they are glazed and fired at a high temperature they are better than most terracotta pots at resisting damage from frost.

In terms of hanging baskets there is also a choice of construction material as well as the obvious differences in size. Plastic baskets are always popular in terms of the initial cost and the fact that they will last for many years. The more traditional wire basket is still a good alternative but it does require some form of lining to retain the compost. For many years this was in the form of sphagnum moss which looks natural and allows plants to be placed in the sides as well as the top of the basket. These days there are a number of alternative types of liner which come either preformed to the shape and size of basket or bought off the roll and fitted by hand. For a really natural look many baskets now come in the form of woven twigs, again in a variety of materials and usually with a built-in plastic liner.

Once the container has been chosen it needs to be filled with compost. Garden soil is not suitable as it is heavy, not rich enough in plant foods, compacts too easily and as a result becomes rather airless and poorly drained. Potting composts come in one of two forms- soil-based and soil-less which many people actually mix together to try to get the best of both worlds. Soil-based compost are essentially those based on the John Innes formula which was established in the 1930’s at the John Innes Institute in the south of England. The original formula does contain some peat together with loam (a mixture of sand, silt and clay), grit and fertiliser- the larger the number the higher the fertiliser content. I believe that a ‘new’ formula with the peat replaced by some other form of organic material will appear on the market very soon. In my view soil-based composts are best used for more permanently planted containers and that for summer pots and certainly for baskets the alternative soil-less composts are more suitable. They are much lighter, drain better and tend to be better value than the soil-based ones. Traditionally they have been made from peat but because we have now realised that our peat bogs have been over-used and as a result have been disappearing rapidly the peat content in composts has been reducing in recent years as more peat-free alternatives have been developed. We are now at a stage where peat products will not be available in the near future so that all soil-less composts will be peat-free. They contain enough plant nutrients for around the first month of growth after which additional feeding is needed.

Having dealt with the ‘mechanics’ we can now move on to the much more interesting part-choosing the plants! Essentially for summer pots and baskets these need to enjoy warm and sunny conditions and produce lots of colour and interest over several months. For this reason we are generally talking about plants from warm or even hot parts of the world which thrive quite happily in our summers but are much less keen on our winters! In the past these have largely been referred to as ‘bedding plants’ which traditionally were used as part of formal summer planting schemes in beds and borders. These were planted out after the danger of frost had passed in late May/early June and flowered through to the first frosts of the autumn. The range of these plants suitable for summer pots and baskets is happily quite large and they fall into three main groups. Each group can be used on its own or all three can be used in the same container for a more varied effect along the lines of a modern, mixed bed or border. The first group is comprised of the larger, taller plants which tend to be used as a centre piece. These give height and act as a focal point for the whole design. There are many to choose from but the most popular ones include Pelargonium, Fuchsia, Osteospermum, Argyranthemum, Diascia and Nemesia as well as such plants as dwarf conifers and Cordyline for foliage and structure. Pelargoniums, often referred to as geraniums were originally from S. Africa and were introduced into the UK in the 19^th century. Their flowers and in particular their cranesbill-like seed heads resembled those of hardy geraniums, hence the confusion over names. They are excellent ‘centre’ plants with their showy flowers and attractive, sometimes scented leaves. They fall into four main groups- Zonal, Regal, Ivy-leaved and Scented. Fuchsias, originally from Central and South America and brought to Europe by returning Portuguese and Spanish explorers, are named after the German botanist Leonhart Fuchs. They are grown for their showy, pendant blooms which are produced over a long period in summer and well into the autumn and come in two forms- bush or trailing. Most are tender in our climate but are perfect for summer and autumn displays in containers.

The second group are what I call the ‘fillers’, smaller plants which produce lots of flower colour and real impact. Again there are many to choose from with perhaps the most popular being Petunia, Begonia, Impatiens (Busy Lizzie), Bidens, Verbena and Lobelia, most of which also come in either the bush or trailing forms. Petunias are a great choice for both pots and baskets as they need no dead heading, the old flowers simply fall away when spent, and they keep on flowering into the autumn. The older varieties are large-flowered bush types but they have been 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 trumpet-shaped blooms in shades of red, blue and pink with contrasting gold stars in the centre of each flower. Begonias are also a good choice and come in two main types- fibrous-rooted and tuberous-rooted. The fibrous ones tend to have smaller flowers mainly in white, pink and red and form small, compact, bushy plants. The tuberous ones are quite different with their larger flowers in more vibrant reds, oranges and yellows and have a more trailing habit. Look out for one called ‘Apricot Shades’ which will produce large numbers of large, 3-4” blooms in vibrant shades of orange and apricot right through until October.

The final group for summer pots and baskets is the trailing group, some of which have been mentioned already in the first two groups. Also in this group are the trailing foliage plants such as ivy (Hedera) and the very useful variegated ground ivy, Glechoma hederacea ‘Variegata’ both of which can easily reach the base of pots or below the base of a basket. Such trailing plants not only increase the impact of flower and foliage but also serve to soften the container itself.

Pots and baskets containing just one variety of plant certainly have their appeal but I think most people seem to go for a combination of the three groups mentioned above. Deciding on the combination is therefore the next task and this where the design techniques which we discussed in terms of beds and borders come into play. These included having variations in height, plant shape (form), foliage texture and, of course, colour. For summer pots and baskets it is probably the latter which is the main consideration and the use of complementary colours eg. red, orange and yellow for a ‘hot’ effect or blue, purple and pink for a ‘cooler’ effect with the occasional contrasting colour for impact is well worth keeping in mind.

I will end this section with some general points about summer pots and baskets. When planting both it always a good idea to use the best compost you can ie. new, not old and with a good amount of fertiliser included.  It is also best to pack the plants in as closely together as you can. In summer displays you want to see the plants and not the container and as they are only temporary plantings and as you are going to look after them well you can afford to cram them in for greater impact. The most important item of care is watering, almost certainly everyday through the summer and in the case of baskets in sunny and also perhaps windy conditions possibly twice a day. Remember you have a lot of plants in a relatively small amount of compost and you have probably placed the container in the sunniest part of the garden. There are ways to reduce the work involved in watering such as automatic watering systems or by adding water-storing gel to the compost. Some composts include these gels or they can be added at planting time. They are particularly good for hanging baskets in really exposed situations. The second most important ‘house-keeping’ item is to feed much more than you would plants in the ground. After the first month or so depending on how rich the compost was to start with additional feeding is necessary either in the form of slow-release granules or liquid feed at least once a week but better twice if you can. This is necessary for several reasons- one, you have lots of plants competing for food,  two, you are expecting these plants to perform at their best for four months or more and three, with all the watering you have to do you are bound to flush out some food before the plants get a chance to use it all. You can reduce this loss by careful watering. With each watering you do need to make sure that the water has got to all the compost by seeing that water is dripping from the base but if you keep this dripping to a minimum you will retain more of the precious feed in the container. Finally in the ‘care plan’ come the usual gardening tasks of dead heading to make sure that no plant produces seed, removing old or damaged leaves, weeding and checking for pests and diseases so that they can be dealt with as soon as they appear.

I hope this has encouraged you to have more summer containers this year as they certainly enhance the more permanent plantings within the garden and will bring you a lot of pleasure and satisfaction. May is the right time to be sourcing plants and getting started with the planting but just remember that you are dealing with mainly, if not exclusively, tender plants and they will need to be protected from overnight frosts and hardened off for a couple of weeks before they go outside for the summer.

To end this month’s blog I have two more short items for you. Firstly the plants of the month from the RHS magazine article on ‘Bee friendly’ plants, the main one of which is the Nettle-leaved bell flower, Campanula trachelium. This is a native herbaceous perennial which is ideal for beds and borders and is a hit with specialist, solitary bees. Its delicate, lavender-blue, bell-shaped flowers provide pollen, nectar and shelter for bees such as the blunt horn and scissor bees. Also on the list for May are Bird’s foot trefoil (lotus comiculatus), Ceanothus, Comphrey (Symphytum officinale) and Rosemary (Salvia rosmarinus).

Secondly and a way to celebrate the Coronation in a week’s time  I thought it appropriate to end with a plug for one of the King’s favourite plants- the majestic Delphinium. These can be grown from seed or from basal cuttings taken in spring as the new shoots appear but the best way to get started for this summer is to buy young plants which will be available in garden centres now. They do require a bit of care and attention such as slug protection when young, a fertile soil to which fertiliser has been added in order to get the plants growing strongly and supporting in some way as they grow but are surely worth all the effort when you see the emerging flower spikes. Once the main spike and all its smaller side shoots have finished flowering the spike should be cut off at its base unless you want to collect seed. When all the spikes have finished the whole plant can be cut down to ground level and given another application of fertiliser which should stimulate it to produce a second crop of flowers in the late summer/early autumn.

That’s all for this month but I will be back with another blog in June and a talk at the Old Railway Line on Saturday 3^rd June as usual at 9-30am in the Tea Room. The main topic will be’ Preparing for late summer colour’ but as always I will include a few other items which have caught my attention. Until then keep well and enjoy your May gardens.