March in the Garden

Having a decent spell of sub-zero temperatures, before winter is over, always makes me feel that some of the overwintering pests may have been wiped out. It calls a temporary halt to such activities as planting bare-root plants but we’ve still got a few weeks left to get on with those tasks that need to be completed before spring is into full swing.
I tend to leave the herbaceous plants in the semi-wild areas of the garden untouched until now because a certain degree of untidiness is good from a wildlife point of view. Also, it’s better than large expanses of bare soil which would require a thick mulch of organic matter to keep weed-free which is an expense I can do without in areas which are designed to be ground cover rather than high-status flower borders.
Having said that, there comes a point where the old, withered, foliage needs to be removed in order that it does not detract from the new leaves which are beginning to emerge. It’s a juggling act between leaving the old leaves long enough that they protect the soil during the worst of the winter weather but not so long that chopping them off risks removing too much of the newly emerging leaves.
For me, the kind of plants which I tend to use as extensive ground cover are knotweeds (Persicaria), Phlomis russeliana, Lady’s Mantle (Alchemilla mollis), Lysimachia and various perennial geraniums. To save time I often use hedge-trimmers, to cut them to the ground, rather than the secateurs deployed to tackle ‘finer’ herbaceous perennials in more formal plantings
I have big stands of perennial grasses in the same areas, chiefly Miscanthus varieties, and these need to be cut down with petrol hedge-trimmers because they are too big and tough to be tackled with anything else. A bladed strimmer, ‘brush cutter’, can be used at a pinch but I find it struggles with cutting them low enough. In order to minimise the length of time that the big grasses are flattened, to nothing, I try to cut them down only once I can see signs of new growth beginning.
If herbaceous plants are beginning to emerge then you can bet your bottom dollar that weeds will already be one jump ahead. Tackling them now, wherever you see them germinating or sprouting from the ground, will save you a lot of grief later on in the season. Hand weeding is the only option where the weeds are nestled amongst ornamental perennials but a chemical weed-killer, if you are not an organic gardener, may prove more effective in areas such as hedge bottoms or under deciduous shrubs and trees.
Hopefully, your garden is now coming alive with all the spring-flowering bulbs that you planted last autumn and also the more established ones from previous plantings. A sprinkling of general-purpose fertiliser, I’m still using ‘fish, blood and bone’, amongst these bulbs and forked in around the emerging border perennials, gives them a chance to grow strongly and replenish themselves. Mulching over bare soil, after feeding, needs to be completed this month before new growth is too advanced.
It gets quite busy this month because, in addition to completing winter tasks, timely seed sowing, under cover, should be underway as well as gently waking up, with sparse watering, any tender perennials that you have been overwintering in the greenhouse or cold frames. If it gets particularly warm, towards the end of the month, it may be possible to sow some hardy annuals outside, directly into their eventual flowering positions, but be ready to throw a cover of horticultural fleece over them if a frosty night is forecast.
Lawns will be growing now whenever the temperature is above 6°C or so. If the weather is dry then mowing with the mower on a high cut will help to keep on top of things. Letting it get really long before the first cut means that when you do get around to it the task will be more strenuous for you, the mower and the grass. If you have the type of mower that benefits from an annual service, and you didn’t get it done over the winter, then it’s worth getting it done now, even though garden machinery workshops will be at their busiest. The ‘tyranny of the lawn’ will only be getting worse from this point on!
I’ll end with the usual reminder that the end of March is really the latest you want to be leaving winter pruning tasks, primarily roses, and all major cutting back procedures such as stooling shrubs like Cornus (dogwoods) and Salix (willows) – grown for their winter stem colour. Again, these will really benefit from a good feed and mulch after they’ve suffered such brutal treatment.