Sage advice: why you should grow more herbs

Herbs not only pack a flavour punch and elevate your cooking, they look good and the gardener's best friends - bees - love them, she told RNZ's Sunday Morning.

If you like mint in your mojitos, give it some space in the garden, she says.

"You can't really buy good mint from the supermarket - you can buy a plant, but they don't last very long.

"They're quite expensive - you know, five bucks for 2-3 cocktails, really - so better to put a plant in the ground and get going with it that way."

Mint is a bit of a "thug", however, and loves to colonise empty spaces in the garden, she says.

"The reason it's a thug is that, when you plant mint, it spreads through underground stems. Most plants will grow up and then they'll stay a nice tidy bush.

"Mint takes one look at any spare soil around it and goes, 'I'll have that too, thanks', and heads off in every direction."

If you've got a small garden and you don't want to be overrun with mint, you need to constrain it's colonising instincts.

"Just get a big plastic bucket, cut some holes in it or even take the bottom out of a plastic bucket, and plant the mint in that and then sink it into the ground, so it has a boundary on either side and it can't get out."

Not that letting it get away need be a disaster, she says.

"It's the most wonderful thing to weed, because you're pulling out big handfuls of minty fragrance, so it's not actually a big problem - I like it."

Parsley is useful in any number of dishes and grows as a perennial in New Zealand.

"I like the Italian flatleaf parsley more than the curly parsley, but as an ornamental plant, the curly parsley is really pretty in the garden. You know, you can pop it into any flower garden."

One plant should give you two years, she says.

"Then, when it goes to seed, leave it in, because when you leave it in, it has these beautiful big umbels of flowers that bees and beneficial insects like.

"It's pretty too, you can use it as a cut flower."

Go with large-leafed varieties of Basil, if you're growing to make pesto, she says.

"I like the small ones. There's one called Greek Mini and then there's Mrs Burns Lemon, which are lovely little romantic names.

"These are tiny little leafed basils and they are just delicious in chicken sandwiches. You make a chicken sandwich with mayonnaise, and you chuck some just a store-bought rotisserie chicken through the blender with these tiny-leafed basils and a little bit of mint, people will always go, 'Wow, what's that?'"

For those among us that enjoy coriander, it will add much to the herb garden, she says.

"For some people, coriander does not taste like coriander, it tastes like soap, so if you're one of those people, you can't get around that. It's always going to taste like soap to you.

"Don't worry about growing coriander, but I really love it."

The trick with coriander is to grow from seed.

"It has quite a long taproot and it doesn't like being transplanted, so if you go to the garden centre, and you buy a pot of coriander and you plant it, it'll go to seed really quickly.

"If you buy a packet of seed and just chuck it in, and scratch it over lightly, honestly, I'm not even kidding, it's not hard to grow, then it will grow and last a lot longer."

Choose a place that gets afternoon shade, she says, because if it gets very hot, it will bolt to seed even quicker. The main thing that frustrates people about coriander is how fast it runs to seed.

"Once again, it's really pretty in flower and, if you let it go the whole way through its life cycle, you can save your own coriander seeds to grind up in cooking."

Sage is useful in the kitchen, ornamental and great for bees, she says.

"My favourite thing to do with sage is to fry the leaves in butter, until they're crispy, and then you just toss it through pasta, like fresh gnocchi or fresh any kind of pasta, it is just delicious."

Sage loves good, free draining soil, she says.

"It's probably best in a pot, if you've got heavy or clay soil, but if you're in the South Island or around Queenstown, Alexandra - all those areas where it's hot and dry in summer - sage is just magnificent.

"It flowers with a beautiful blue flower as well."

Oregano is one of the most beneficial plants for bees, she says.

"A few years ago, some apiary students in the UK went to the garden centres and sat around looking to see which plants the bees actually landed on.

"You see the things like lavender have the labels that say these are bee friendly, but the plant that was the most visited by bees was actually flowering oregano."

Rosemary is another Hallinan favourite.

"Who wouldn't love rosemary? I mean, you can't have a roast potato without rosemary."

Kiwis tend to think of it as a winter herb, but it will need attention in summer, she says.

"If you don't cut it through spring and summer, then the volatile essential oils in its foliage, they get quite concentrated and so it can taste a little bitter.

"If you do nothing else, if you're not going to eat any of your rosemary, just still give it a good trim in summer, and then that fresher foliage will be the stuff that you're eating come next winter and autumn."