When to plant rosemary - experts explain why temperature is key to a successful herb garden

If you’re looking to ditch the supermarket and grow rosemary at home, swotting up on when to plant rosemary should definitely be on your to-do list.

After all, there are so many perks to growing your own rosemary. As well as filling your garden or windowsill with a fragrant scent, this plant can also attract pollinators and be a welcoming (and delicious) addition to your herb garden. But before you start reading up on how to prune rosemary and how to propagate rosemary, you need to plant it at the perfect time.

Yes, one of the biggest herb garden mistakes you can make is planting your herbs at the wrong time - and this is the case with rosemary. The wrong temperature and the wrong conditions have the potential to wreak havoc on your rosemary, which is why knowing when to plant rosemary is key.

While there are many herbs that you can grow from seed, rosemary is incredibly difficult to grow from seed. It’s not impossible, but it will likely take years for the plants to be large enough for harvesting. So, it’s better to buy rosemary plants or grow from cuttings instead.

This is echoed by the gardening experts at GardenBuildingsDirect.co.uk, who say, ‘Basil, mint, parsley and chives are simple to grow in containers straight from seeds, whereas herbs such as rosemary and oregano are easier to grow from a small plant.’

If you buy a rosemary plant and plan on growing the plant in its container, you don’t need to do anything else. But if you want to transplant the plant to your garden borders or into a much larger pot as part of your container garden, you’ll need to choose the right time to plant rosemary. In some cases, you may have to keep it in the pot for a few months before taking the plunge.

When to plant rosemary

Ideally, you should aim to plant rosemary during the mild spring months. This makes it one of the best gardening jobs to do in March.

Morris Hankinson, Director of Hopes Grove Nurseries, says, ‘Spring is the best time to plant rosemary, especially after the last winter frost! Timing is essential as it allows the plant to establish roots in warm soil and take advantage of the full growing season.'

He adds, ‘Spring can also provide rosemary with a full growing season to mature and strengthen before the cold winter months.’ You don’t necessarily have to stick to this exact timescale, though, as there is some flexibility in this.

If you wanted to, you could plant rosemary anytime from spring to early autumn, as long as the temperatures are mild enough. You should also make sure that you plant your rosemary in free-draining soil in a fairly sunny location.

Morris Hankinson

Morris Hankinson is the founder and managing director of Hopes Grove Nurseries Ltd, the UK’s only specialist grower-retailer of hedging plants. He established the thriving business in 1992, shortly after graduating with a Commercial Horticulture Degree from Writtle College, Essex.

When not to plant rosemary

While it’s important to understand when to plant rosemary, you should also know when not to plant rosemary. And there are two prime times to avoid.

Firstly, you should avoid planting rosemary in the height of summer, as the young plant will likely struggle with heat stress and may not survive the ordeal.

However, if we have a cooler summer and you can provide your new rosemary plant with shade and water, you may be able to get away with it. Just remember to water regularly to ensure the new plant can root itself into the ground.

Secondly, you should avoid planting rosemary during the winter months. And while established rosemary is fairly hardy and can tolerate the odd frost, newly-planted rosemary won’t be able to.

In fact, it’s likely that the combination of intense waterlogging, frost, and cold temperatures will kill the plants before they have a chance to take root.

What you'll need

FAQs

What month do you plant rosemary seeds?

If you want to grow rosemary from seeds, you should do so indoors from mid-February to April. If you want to sow directly into your garden beds or borders, however, it’s best to wait until May to ensure the soil temperature is warm enough.

And while there’s nothing wrong with planting rosemary seeds, be warned that the process can be lengthy. It can sometimes take years for rosemary plants to establish themselves, so if you’re desperate for a free supply of this herb, it might be better to buy rosemary plants instead.

Does rosemary come back every year?

As rosemary is a perennial, it should come back every year as long as it’s happy in its location and well taken care of. To ensure it comes back annually, you should keep on top of pruning, plant it in a sunny location, and keep it well-watered.

Does rosemary like sun or shade?

Rosemary plants are sun-worshippers and thrive in full sun. David Denyer from Eflorist explains, ‘When planting rosemary, the key is to mimic its Mediterranean homeland. It craves sunshine, good drainage, and interestingly, a bit of neglect.’

‘You'll want to choose a spot that gets plenty of sun. Rosemary is a real sun worshipper. The optimal soil or best potting mix for rosemary should be well-draining to prevent soggy roots, which can be its downfall. A touch of grit or sand mixed into the soil can help with this.’

However, if you can only offer them partial sun, you should still be able to grow a happy and healthy herb garden.

Rosemary’s love of the sun is one of the reasons why it makes such a good container herb. By planting your rosemary plant in a pot, you can move it around the garden and chase the sun to ensure it gets all of the sun it needs.

So, now you know when to plant rosemary all you need to do is get cracking!