The Garden in March - ‘Springing into Action’
At last magical March has arrived and my ‘new’ book informs me that ‘as the weather improves and the soil warms, nature herself is stirred into action’. Gardeners, if they are anything like me, are affected in the same way after what seemed like a very long and wet winter and I’m sure are keen to get the growing season underway.
With March fast approaching I was only thinking the other day about the early spring plants which I wouldn’t want to be without in my own garden. My first of five is the Narcissi in all its wonderful forms. My second is the Hellebore which have actually been flowering all through February already. Thirdly I love to see Primulas in the spring, especially the simple but beautiful wild Primrose, Primula vulgaris. My fourth is the, in my view undervalued, Pulmonaria (Lungwort) one of the earliest flowering herbaceous plants. My fifth might surprise you as it is a showy, some might say blousy, plant and that is the stunning Camellia. I wonder what your five choices would be?
Looking back through past blogs I see that in March 2021 unsurprisingly I was concentrating on our own garden here in West Wales and highlighting the plants which Teresa and I had been enjoying through February and into March which included Snowdrops (Galanthus), Narcissus, Helleborus, Primula, Hamamelis (Witch Hazel), Cornus mas, Sarcococca (Christmas Box), Chaenomeles and Camellia. The March 2022 blog came from the gardens at Aberglasney in all their spring glory. In March 2023 I was concentrating on ‘Growing your Own’, a topic which I will return to later in this blog. All of these can still be found on the Old Railway Line’s website under ‘blogs’, ‘show tags’ and ‘monthly guides’.
For the blogs and talks this year I propose to follow up the many and varied suggestions which I received from the audience during the last talk of 2023 back in October. The majority concern ‘how to do items’ most of which are relevant at particular times of year. I would like to start off with a topic dear to my heart which is about soil improvement in general and making homemade compost in particular. I’m sure that most of you are aware that I am a great believer in looking after our soils so that they in return look after our plants. There are a number of different soil conditioners ranging from animal manures, spent mushroom compost, composted straw and bark, seaweed and soil improver from green waste sites all of which will benefit soils by adding plant nutrients as well as organic matter which provides food for vital soil organisms and eventually breaks down to produce humus, a magical, sticky, black material which helps to bind the soil particles together in loose, crumb structures and aids water retention. There are of course two other sources of soil improver which are free and, as they are available from within our gardens, have a low carbon footprint,- leaf mould and homemade compost. The former I will deal with later in the year when it is more topical but now is as good a time as any to start making your own compost which is usually described as ‘garden compost’ in order to distinguish it from ‘potting compost’. This can be made in heaps, wooden bins or plastic containers but they must be of a good size in order for bacteria to work well and to generate the heat which will also help to break down the organic matter and to kill off weed seeds and some pests and diseases. A minimum of around 1 cubic metre is generally the recommended figure. It is also a good idea to have at least two heaps or bins so that one can be rotting down as the second is being filled. Basically, to successfully produce ‘good’ compost the heap or bin requires two types of material- nitrogen-rich material such as grass cuttings, uncooked vegetable waste from the kitchen, any green plant material including weeds (as long as they have not gone to seed or have problem roots such as couch grass) and carbon-rich material such as shredded bark, shredded paper and cardboard and shredded woody prunings from shrubs and herbaceous perennials. The real secret is to mix such materials up as much as possible. With heaps and open-fronted bins it is recommended that after three months the whole heap is turned out and then re-mixed as it is returned. However, with plastic bins which often only have a small hole at the base this turning is not really possible. Instead, I keep an old fork next to the bins and give the contents a quick mix every time new material is added. It is particularly important to mix grass cuttings really well as in layers on their own they can pack down and begin to rot without the presence of air which simply produces a smelly, slimy mess! To speed up the decay process it is also a good idea to add some form of activator from time to time as the heap builds up which adds extra nitrogen. The best one is animal manure if you can get hold of it (not literally of course!) as it contains lots of soil organisms as well as nitrogen but failing this there are several activators on the market although I just use a handful of chicken fertiliser pellets. Water may also need to be added from time to time if the material is on the dry side but at the same time it shouldn’t be too wet as it leads to a lack of oxygen. A smell of rotten eggs means that the heap lacks air and an ammonia smell indicates too much nitrogen-based material. It varies with the size of the heap and the materials used but after 4-6 months the compost should be ready to use when it will be brown and crumbly and smells like the woodland floor in autumn. All being well, therefore, a heap or bin started off in March should be ready to use by the end of the autumn in a number of different ways. It can be an important ingredient in homemade potting compost, can be used to improve the soil when planting and as a mulch around newly planted plants but, in my opinion, is best used as a top dressing on the soil surface in late winter or early spring. This will be incorporated into the soil by earthworms and other soil organisms and will return all the goodness to the soil where it came from. This is natures way of recycling nutrients and as such has a lot going for it!
One of the topics mentioned by quite a few people last October was the taking of cuttings. This method of plant propagation is, of course, an excellent way of producing new plants that will have all the same characteristics as the parent material unlike plants which are grown from seed which will always have slight variations. It is also very cost effective and can be successfully carried out on many different types of plant without too much difficulty and with little more equipment than a sharp knife and some potting compost. There are several different methods of taking such cuttings which are best done at certain times of the year. The three main types are stem, leaf and root cuttings which will all be covered this year in blogs and talks at their most suitable times. This month’s type is softwood stem cuttings which are best done in spring and early summer when there is plenty of new growth on the parent plants. ‘Softwood’ is perhaps a bit of a misnomer as the stem to be used is not ‘woody’ at this stage in its life and possibly a better name would be ‘soft material’ cuttings. They work best when the new growth is vigorous as when such material is cut some of the cells in the cambium (outer) layer are stimulated to produce new, adventitious (meaning ‘added’) roots. Such adventitious root growth is also helped by naturally occurring hormones called auxins which accumulate at the base of a cutting. These can be supplemented by synthetic auxins which are available in powder and liquid forms. Such cuttings are generally made from the tips of shoots (tip cuttings) but others can be made from the base of plants (basal stem cuttings). This is a particularly good method for herbaceous perennials such as Achillea, Anthemis, Campanula, Delphinium, Dicentra, Gypsophila, Lupinus, Lychnis, Malva and Polygonum. They are taken when the new shoots at the base are large enough to handle (3-4”/8-12cm). A little soil needs to be scraped away and the shoot cut close to the crown of the plant and if at all possible, but not essential, with a small amount of root attached. As with all soft cuttings it is a good idea to store the cut shoots in a polythene bag until planting up time just to keep as much moisture in the cutting as possible. This is the key to success, reducing moisture loss to a minimum until new roots form by keeping the cuttings out of the sun and wind and in a high humidity environment. Soft tip cuttings can also be made from a wide range of plants including Ajuga, Artemisia, Centaurea, Dianthus, Euphorbia (but keep any white sap away from skin), Gypsophila, Helenium, Helichrysum, Lysimachia, Penstemon, Phlomis, Sedum and Teucrium as well as from more tender perennials such as Argyranthemum, Fuchsia and Pelargonium. A shoot tip of 3-4”/8-12cm long is cut from the parent plant just below a node (leaf joint), the lower leaves removed and the cutting placed in a polythene bag. Cuttings of either type can be soaked in a fungicide solution and/or dipped into hormone rooting powder or solution if required before being ‘dibbed’ into potting compost, given a light watering, covered with a polythene bag and placed into a shaded, sheltered spot outside, in a cold frame or in the case of the more tender plants inside the house, porch or cool greenhouse. They will need to be checked for moisture from time to time and for the removal of any which have wilted or starting to show any signs of rot. New leaves will start to form when rooting has taken place and once the cuttings are growing strongly they can be potted up to grow on. As far as the potting compost is concerned it does not need to be particularly rich in nutrients but it does need an open structure which allows both air and water to enter and drain through if necessary. For this reason many gardeners add sand, grit, perlite or vermiculite to ‘open up’ the compost to aid good root growth. The same method can also be used with many shrubs as well as herbs but generally in the early summer rather than the spring when the plants have developed the right sort of tip growth. The success rate of these may be lower but there is always a second chance for cuttings to be taken in the late summer in the form of semi-ripe cuttings which will be dealt with when the time comes.
March is also a good month to prune a number of shrubs and I imagine that most gardeners would put roses at the top of this list. All the rose types apart from ramblers which are pruned in the late summer need to be pruned when they are dormant or semi-dormant ie between leaf fall in the autumn and when the buds are swelling and about to break in early spring. Such pruning is done to build up a healthy, open framework of shoots that will produce a good display of flowers. I think most gardeners do their rose pruning in late February or early March when the worst of the weather is over and any damaged, diseased or crossing wood is easy to identify and remove, cutting back to disease-free white pith. The basic principles of pruning any shrub or tree apply- using clean, sharp tools and making an angled cut just above a bud which faces in the desired direction, usually outward facing to avoid congested growth in the centre of the plant which restricts air flow. If the buds are difficult to see the shrub can just be cut to the required height and any stubs removed later as the buds begin to develop. The height of the cuts depends on the type of rose and I dealt with this in some detail in an earlier blog (Feb. 2021 under ‘Gardening Tips’) but the summary is as follows:-
Hybrid Tea roses (large flowered bush)- 1’/30cm above ground level
Floribunda roses (clustered flowered bush)- 1.5’-2’/45-60cm
Shrub roses incl. David Austin bush roses- shorten shoots by up to one third
Climbing roses- tie in strong shoots to create framework and shorten side shoots to 6”/15cm
Just one last point, don’t forget that the harder you prune the more vigorous the regrowth will be ie prune weaker shoots harder/lower than strong shoots.
As I mentioned at the start of this section there are other shrubs and climbing plants which benefit from a prune in March. Many people prune summer flowering Clematis in February but the first part of March is still a good time. Basically, leave spring flowering, group 1 plants alone (these can be pruned if necessary after flowering) but prune the summer and autumn flowering, groups 2 and 3 plants quite hard otherwise most of the flowers will be high up on the pergola, fence, wall etc and not easily appreciated. These two groups can be pruned slightly differently but around 2’/60cm above ground level is not a bad general figure to aim for, pruning just above a pair of strong buds. March is also the time to prune the coloured stem Dogwoods (Cornus alba) which hopefully have been providing lots of winter colour. Left unpruned they can become large, rather tangled shrubs with the best colour only on the newest shoots. Traditionally all shoots are pruned back to within one or two buds of the old growth near the base but a less drastic method is to prune just one third of the shoots in this way and to extend the pruning programme to a three-year cycle. This is also a good time to prune summer flowering shrubs such as Buddleja, Lavatera, Sambucus (Elder) and Leycestaria (Pheasant Berry) again cutting back hard to within one or two pairs of buds of the older, woody growth near the base. Hardy Fuchsias can be pruned even harder, right back to ground level, although in milder districts many gardeners just prune back to live, healthy wood. If you would like more details on this and some other March jobs to keep you out of trouble then have a look at ‘The Garden in March 2021 under ‘Monthly Gardening Guides’.
Finally for this month I turn my attention away from the ornamental garden to the vegetable plot. Some vegetable seeds can be sown indoors in February but for outside sowings it is sensible to wait until March when the soil has had a chance to warm a little. A good way to judge when the soil is ready is to look out for weed seeds beginning to sprout. For more detail on growing your own vegetables and fruits have a look at the blog for April 2021 under ‘Gardening Tips’ where I looked at the good reasons for doing so and the different methods which can be used. I also covered this topic again in March 2023 in which I looked at the main vegetable groups, crop rotation, growing methods including bed systems and containers, fruit groups and their best growing conditions and edible flowers. In our own garden Teresa and I don’t have a lot of room spare for ‘grow your own’ so we concentrate on what we really like to eat as well as higher value crops. We have created three raised beds, grow quite a lot in pots and troughs and have a small lean-to greenhouse for tomatoes. The raised beds were all sown with a green manure crop last autumn and as we enter March this has all been cut down and forked into the soil surface with any old potting compost and our own garden compost on top of it so that the beds are ready for sowing and planting. We like to get an early crop of broad beans for which we use ‘The Sutton’ which is a dwarf variety. These have been sown in pots in February in the greenhouse and they will be planted out when a few inches high during March after a little hardening-off. One of the three beds is always used for runner beans later in the year but we try to grow an early lettuce crop in the space which will mature before the beans are growing away in June. For this and the other two beds we tend to use plug plants rather than growing from seed in order to give us a good start on the season although we do sow larger seeds such as spinach, chard, sugar snap peas and a variety of beans. As for the pots in March these will be topped dressed with new potting compost and some fertiliser ready for growing lettuce and later on dwarf beans. We also have three larger pots (they are really planting ‘bags’) which we use for early potatoes. This compost is replaced each year and the old compost goes onto the raised beds where we don’t have room to grow potatoes. Last year these three bags planted from early March to mid-April produced around 10 lbs of lovely Charlotte potatoes. As I write this year’s seed potatoes are sitting in egg boxes in the utility room quietly ‘chitting’ away. This is where shoots start to grow from the eyes on the potatoes so that on planting in a few weeks’ time the potatoes are already in growth and therefore get off to a good start. We simply put 5 potatoes in the bottom third of each bag and as the growth comes through the surface more compost is added to encourage longer shoots on which the new crop will form and to give the top growth some frost protection. This is a very similar process to that of earthing up potatoes in the form of a ridge when grown in the ground. If it does get unusually cold we just put the bags into the greenhouse overnight or for a few days. Last year we harvested from the end of June until the end of July and were still eating our own potatoes at the end of August. Some of the bags sold for this purpose have flaps near the base through which the potatoes can be harvested but we find it easier to tip the whole bag out onto a plastic sheet on the lawn so that every potato, no matter how small, can be harvested. The compost is then returned to the bag and a different, second crop grown in the rest of the summer. Early potatoes need around 12 weeks to produce a reasonable crop and around this time the foliage will be beginning to show signs of wear and tear. We also grow as many tomatoes as we can, partly in the greenhouse and partly outside in pots. Some are grown from seed and the rest bought as plants to make up the numbers. Last year from six cordon grown plants in the greenhouse (we like to grow ‘Sungold’) and another six in outside pots (a mixture of red and yellow ‘Tumblers’) we enjoyed over 500 lovely cherry tomatoes and were still eating them into October. Finally, we also grow a variety of ‘salad leaves’ in up to four troughs either in the back porch or greenhouse. These are quick growing plants often labelled as ‘Speedy Veg’ on the seed packets which can be cropped within a month of sowing and treated as a ‘cut and come again’ crop for the second month. The trough can then be top dressed with some new compost and re-sown with such things as Rocket, Leaf Salads, Mizuna and Lamb’s Lettuce. This method can also be used through the autumn and winter with some hardier plants such as Winter Purslane and as I write this piece we have three productive troughs in the back porch all of which were sown back in the autumn.
Just one final reference to the suggestions made back in October, one of which was creating garden ponds. This is a large topic and would take up a whole talk, if not more, and for this reason I think it best just to refer anyone interested to two blogs which I wrote in January and February of 2021 to be found under ‘blogs’, ‘show tags’ and ‘gardening tips’.
Well, I think that’s a very busy blog for a very busy month and I hope it will give you a few new ideas to try out in your own gardens. If you are anything like me you can’t wait to get out there into your ‘happy place’! In next month’s blog and talk ‘Between the Showers’ I will be looking at lawn care, summer bulbs, growing figs, April pruning and some of the basics of bonsai- something for everyone I hope.
Until then keep well and enjoy your time in the garden.
Keith.