As summer flickers and fades to autumn, finding the opportunity to carry out routine garden tasks can be challenging.
Confronted with a combination of dwindling day length, cooler temperatures and faltering growth levels, it’s all too tempting to put off standard chores such as weeding, pruning, mulching, hoeing, seed saving and sowing. But that would be a mistake.
The truth is, every hour spent working in the garden over the coming weeks will pay rich dividends down the line, from boosting soil health and ensuring a colourful, productive plot, to getting a jump on spring jobs and saving energy on repetitive, time-consuming tasks.
Spread a weed-suppressing organic mulch on bare soil this month, for example, and not only will you help prevent any fresh germination of weed seeds over the coming months, but you’ll also do a lot to kill off any young weed seedlings that have freshly emerged. Stopped in their tracks, they won’t get the chance to grow into large deep-rooted plants laborious to remove next spring.
These kinds of early autumn mulches also do a huge amount to protect soil structure and prevent winter leaching of vital nutrients, resulting in healthy, happy plants that are considerably more vigorous, as well as resilient to attack from pests and diseases. Suitable mulch materials include well-rotted garden manure, homemade garden compost, lawn clippings, seaweed, chopped bracken, straw and chipped hedge trimmings, as well as commercially-produced mulches (see envirogardenandhome.ie; and geeup.ie).
Spread them to a depth of 5cm-7.5cm (1.9in-2.9in), keeping them out of direct contact with the stems of woody trees and shrubs as well as the crowns of plants to avoid the risk of disease and decay.
In vegetable beds where weedy growth is a persistent problem or in areas where you want to create new plantings or plant a hedge, spread cardboard followed by a thick layer of organic mulch, before finishing off with a top layer of strong black polythene sheeting. Weigh the edges of the latter down by wrapping them in old planks or trenching them into the ground. Come next spring and the beginning of a new growing season, all you’ll need to do is peel it back.
Sowing seed of green manure at this time of year is another excellent way to provide empty vegetable beds with a protective winter coat while simultaneously boosting soil health and fertility.
Also known as living manure, this technique uses a range of generally fast-growing plants to create a temporary living blanket of greenery, which is later cut, strimmed or scythed down.
Some gardeners like to dig the trimmings into the ground while others leave them as a cover mulch to slowly rot down and release the nutrients contained in their foliage. Either way, there are multiple benefits for soil and plant health, from the suppression of weed growth and common pests and diseases to improved soil structure and greater resilience to both drought and winter flooding.
Species of green manure suitable for sowing in September include phacelia, mustard, crimson clover, Japanese oats and Hungarian vetch. Stockists include most good Irish garden centres as well as a selection of online suppliers including Cork-based fruithillfarm.com, Dublin-based mrmiddleton.com and Sligo-based quickcrop.ie.
Green manure isn’t the only thing well worth sowing this month. If you have a polytunnel or glasshouse, you can sow seed of spring cabbage, kale, hardy lettuce, rocket, lamb’s lettuce, Swiss chard and oriental leafy greens (see nickykylegardening.com for tips on winter polytunnel growing).
It’s also well worth sowing seed of some hardy flowering annuals to give you stronger, more vigorous, more floriferous plants that will be earlier into flower than their spring-sown equivalents. Suitable candidates include ammi (Ammi majus); cornflower (Centaurea); love-in-a-mist (Nigella); marigold (Calendula), corncockle (Agrostemma) and Shirley poppies (Papaver rhoeas).
If you grew these in your garden or allotment this summer, then check the plants for ripe seed-heads from which you can harvest a wealth of homegrown seed. Share any surplus with friends or store it in paper envelopes placed in a cool, dry, dark place for later use. The joy that comes from growing plants this way is a special one, plugging us into the seasonal rhythms of the growing year and its natural cycle of life, death and rebirth.
Growing plants from seed is just one way to enjoy early autumn’s bounty. September is also an excellent time of year to propagate many kinds of summer-flowering hardy herbaceous perennials by division, using a clean, sharp knife, spade, or two garden forks placed back-to-back to separate any large, well-established root balls into smaller but still viable pieces. These can then be immediately replanted into the ground or potted up and grown on until needed. Suitable candidates include delphiniums, hardy geraniums, hosta, day lilies (Hemerocallis) and phlox.
Planting spring flowering bulbs is yet another of those autumn chores where the rewards are great. By concentrating on reliably hardy perennial varieties, the hard labour of burying those fleshy bulbs deep in the ground will also be repaid for many years to come. Suitable candidates include different kinds of narcissus, allium, camassia, scilla, crocus, chionodoxa, Fritillaria meleagris and Iris reticulata.
Many of these spring flowering bulbs can also be planted in gentle drifts in traditional wildflower meadows or mini-meadows, where their colourful blooms will extend the season of interest. Where conditions are right, some will even self-seed over time.
September is also a good time to scythe or strim these kinds of true wildflower meadows as a way of keeping soil fertility levels low (this greatly helps to nurture a biodiverse meadow) as well as creating the optimum conditions for successful germination of any recently ripened seed.
Just make sure to leave the cuttings on the ground for a few days to allow that ripe seed to spill, before removing the former and adding them to the compost heap.
Finally, some (but not all) hedges should be pruned in September. Examples include fast-growing species such as privet and Lonicera nitida as well as yew (Taxus baccata), beech (Fagus sylvatica), and silverberry (Elaeagnus). A task for a still, dry day, make sure to take suitable safety precautions as regards the use of ladders and sharp tools, especially power tools.
For reliably straight lines, don’t kid yourself that your eye is good enough (nobody’s is). Instead use a guide line of twine tautly stretched between two canes.
This week in the garden
- Plant onion sets into a sunny, free-draining spot in the garden where the soil hasn’t been recently manured for an early crop next year. Suitable overwintering varieties include ‘Radar’, ‘Snowball’ and ‘Electric’.
- Early autumn frosts can often threaten at this time of year, damaging or killing tender plants that would otherwise put on a good display for several more weeks, so try to keep some horticultural fleece at hand to throw over summer bedding displays and other vulnerable species.
Dates for your diary
- Patthana Garden Open Day Kiltegan, west Wicklow (W91X789); tomorrow, Sunday 21st September. Open day with plant sales and refreshments; patthanagardenireland.com.
- Joint Garden Open Day June Blake’s garden, Tinode, Blessington, Co Wicklow and Jimi Blake’s garden, Hunting Brook, Lamb Hill, Co Wicklow; Saturday September 20th (11am-5pm). Plants sales and refreshments, with all profits to Gaza, see juneblake.ie and huntingbrookgardens.com.
- Exotic Gardening Scoil Mhuire Naofa, Station Road, Carrigtwohill, Co Cork; Thursday, September 25th (8pm). A talk by Steve Edney, owner of No Name Nursery in Sandwich, UK on behalf of Cork Alpine Hardy Plant Society, admission €10.
