Home LifestyleGardening September Gardening Guide

September Gardening Guide

by admin

September is the time to start thinking ahead to next year’s garden.

We never know how soon frost might come – we may have many more weeks before the temperatures dip below zero, but it could come far quicker than that.

When you have tender perennials in the garden, there is a bit of a game of chicken to play: how long should you wait before protecting plants against frost, or bringing them in for the winter?

As long as the frost stays away though, there’s still much to enjoy in the September garden. Whilst some plants are starting to look past their best, others, like dahlias, can put on their best display at this time of year. Deadheading is likely to take up much more of your time, but is so worth it to prolong the colour in the garden.

Here are some of the jobs you can be doing in your garden this month:

Begin collecting seeds and taking cuttings

Collect up poppy seeds when the seed heads have dried up.

Your garden may be fading as the year comes to an end, but there is still so much potential. Collect seeds from plants such as nasturtiums and poppies, and you’ll have a head start on next year.

Collecting poppy seeds is easy. Wait until the seed head has gone a bit grey – you’ll notice the top of the seedhead looks like it’s popped open a bit – they’re basically like little salt shakers, because that’s exactly what they do – they shake the seeds out a few at a time. If you don’t want millions of poppies all over the garden you’re best to cut them off and you can easily collect the seeds in an envelope, so that you can plant them where you actually want them.

As you consider how you’ll overwinter tender perennials why not think about taking some cuttings, too? This can be done relatively easily from fuchsias, roses, salvias and even geraniums / pelargoniums – this is a great video by Monty Don to explain how you do this.

Deal with slugs and other pests 

Nematodes to treat slugs

At this time of year, using nematodes to control some of the pests which have become problematic in the garden can be a great idea.

You can use this chemical free, environmentally friendly pest-control method now and it can help control the numbers of slugs, vine weevils, daddy long legs & more that appear in your garden next year. You simply mix the nematodes with water and apply to the garden.

In its first year, the garden in our Lowton new-build was overwhelmed with slugs – literally thousands of them. We used nematodes in year 2 to control them, applying them periodically throughout the year. I must admit, we were doubtful as to what difference it was making, because those little guys just kept showing up. But in the third year, we had far fewer slugs.

The following year, we didn’t use nematodes because we thought we didn’t need them any more… mistake! They returned in abundance and munched through everything they possibly could. I suspect that applying nematodes late in the season prevented the laying of lots of eggs – and led to the reduction of slugs the following year. So I’d definitely advise doing a late application this  month, before the soil gets too cold, in order to keep their numbers under control next year.

I’ll also be doing a preventative treatment of the lawn for leatherjackets (daddy long legs larvae). Again, you can use nematodes for this. I know several neighbours have had their lawns destroyed by these little blighters, who eat the lawn as they hatch. I’ve spotted a lot of daddy long legs on our lawn lately, and a few patches beginning to appear, so have decided to take action before it’s too late!

My ‘Red Devil’ Rose was suffering from black spot, as seen on its leaves.

As well as pests, look out for signs of disease in the garden, too. This time last year my ‘Red Devil’ roses were covered in black spot. I cut them right back to the ground and hoped for the best. And they survived! This year they put on lots of new growth and were back in flower. Phew.  So, if your roses are showing signs of black spot, make sure you remove all the affected leaves and destroy them (don’t add them to your compost).

Start planting for autumn, winter and spring

Bulbs being planted around a tree

I love planting bulbs for spring – and September is the month to get started. I’ll be planning a mixture of new bulbs and also some of the daffodil, hyacinth, crocus and iris bulbs I saved from last spring. On top of that, this year I’ll be adding more alliums, yet more muscari, some Anemone De Caens. However, don’t plant tulips yet – it’s best to wait until November.

This is also a good time to start creating some autumn / winter containers. You can also add colour with plants like cyclamen, heucheras and primoses. Use early spring bulbs to add additional interest early next year with dwarf daffodils, iris and crocuses.

This month I’m also going to plant up some prepared hyacinth bulbs for indoors – not sure if we’ll get the timing right but it could mean some lovely scented flowers for Christmas, fingers crossed!

Prepare for colder days ahead

Pink rose covered in frost

Frost will kill off many of your tender plants – so make sure you plan ahead for when the temperatures drop.

As I mentioned in the intro, we’ll have to play this one by ear. We may get a glorious warm September, in which case you can hang on before beginning to protect plants from frost. But its always good to be prepared.

If you have the space – in a greenhouse or a conservatory – you can bring tender potted plants in. Otherwise you’ll need to think about covering them with fleece or a covering of mulch to protect them over winter. Unfortunately we don’t have a glass greenhouse or a conservatory – so we’ll do our best in an unheated mini-greenhouse, with plants wrapped in gardener’s fleece. I’m hoping not to have to do this for a few weeks yet.

If you let your houseplants spend some time outside in August, make sure you bring them back in now. You can also bring herbs like parsley, chives and mint indoors to keep on your kitchen windowsill to enjoy fresh herbs for longer.

If you’re growing tomatoes, before the weather turns cold cut off any remaining unripe trusses. Bring them indoors to ripen up.

Once the first frosts have come, I’ll be digging up my dahlias and storing the tubers over winter. But I am happy to wait until frost comes before I do this – so details about how to do this will be in the October update.

Plan ahead for next year’s garden

Red poppies growing in a garden in September

As it  becomes increasingly obvious that the year is coming to an end, it’s a good time to reflect on what’s worked well in your garden this year, what hasn’t, and what you’d like to do differently next year. For example, I’ve loved my cosmos again this year so definitely want to grow it next year. But I might try some slightly shorter varieties to avoid the late summer ‘flop’. And in terms of edibles, I’m going to move away from brassicas that are easily gobbled and maybe focus more on onions, garlic, cucumbers… and the surprise star of my garden at the moment – sweetcorn!

Make a note of the lessons you’ve learnt this year – it’ll give you a valuable head start on next year.

In need of some help in your garden?

Check out the local gardening companies we have listed in our Newton-le-Willows Local Directory if you need help in the garden – from mowing the lawn to total landscaping projects.

About the author:

My name is Gemma. I’m the editor of Newton-le-Willows News and a very keen but amateur gardener. I enjoy growing flowers and edibles in my garden in Golborne. You can follow my garden on Instagram @gandtgarden.

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