With lives lost and countless homes and businesses devastated, it may seem trivial to talk about gardening, but for many our gardens are a source of joy and a place that helps us recover after a crisis.
Gardener, author and broadcaster Lynda Hallinan joined Jim Mora to answer questions on how to restore a weather-damaged garden.
A flooded garden in Kumeū. Photo: Supplied/ Christaan Head
Listen to the full conversation
If you've got a garden in a suburban area that's flooded, and you've got vegetables it's better to cut your losses and pull them out, Hallinan says.
“You're going to have to let that soil settle for a little bit and try and hope for some sunny days to use natural anti-bacteria bleaching properties of UV light.”
Dealing with silt is problematic, she says.
“You have mud, and the problem with mud is that when it dries out, you end up with a layer of almost impermeable, solid concrete-like soil that destroys any aerobic ability underneath it.
“You'll find that you'll have trees and shrubs that look like they’ve survived a flood, and then six months later, they turn up their toes and die because you've got fungal problems now a couple of layers down on the soil.”
Lynda Hallinan Photo: Lynda Hallinan / Facebook
A number of listeners wanted to know what to do with flood-damaged and stressed trees.
“I'd always recommend if you've got an enormous tree that's threatening say your property or your neighbour's property, get an arborist just to be on the safe side. Some selective pruning can go a long way, you can bring trees down in size, take off really long, overhanging branches that might be causing some balance issues for trees.
“And certainly, pruning anything is a good idea if you've gone through a period of stress in a garden, so if it's a drought or if it's a flood.”
Photo: 123RF
My coastal property east of Whangarei was inundated by four high tides during Gabrielle, should I trim the dying tips and twigs now off my primarily native shrubs or just wait to see which, if any, survive their salty bathing?
“Salty soils and salt contaminated soils can do just as much damage as just pure water.
"I would actually chop things back because of the time of the year. We're still in a period of growth. If you were to go and chop things back, such as native shrubs, they should come back and produce some new growth.
“I'd hose them down first, and that sounds ridiculous if you've had all this water, but getting filth and getting salt off the leaves of plants will also help them to photosynthesize.
“The stuff that's really burned and badly damaged, absolutely trim that off, but everything else give it a good watering. Just to try get those leaves growing again.”
Is it worth trying to save my waterlogged fruit trees – peach, plum feijoa and apple. Have avocados in another position not waterlogged, but wet.
“Avocados that sit in waterlogged soils are very, very susceptible to Phytophthora, which is a fungal disease, root rot basically, so the tree will just up and die.
“I would leave the avocados in, because if they're going to die, they will make that decision for you. And you'll see pretty quickly in a couple of months’ time - they'll either be alive or dead.
“There's no in between with avocados they don't sort of struggle on for a long time.”
Flood-affected deciduous fruit trees are at a vulnerable stage, Hallinan says.
“The problem that we've got is that this has happened at the worst possible time for fruit trees, because obviously a lot of them would have been laden with fruit.
“But also, because they're deciduous, you just can't pick them up and move them the way that you can prune back an evergreen shrub and shift it, so you may potentially lose them. And same thing basically it's really a wait and see.”
It is worth trying to improve the drainage around them, she says.
“Dig just little trenches with a spade and try to direct some of the water away from them.
“And also, just try to aerate the roots. It sounds nuts, but you could use a water blaster and try and blast silt off around fruit trees just to try to get through to that bottom layer of soil again, but it's really just hit and miss. There's no easy answer, unfortunately.”
Carrots Photo: 123RF
A general question, has Lynda got any advice on getting swathes of convolvulus out of raised veggie garden beds?
“I've got the exact same problem because a few years ago I got to tray load of free soil which you shouldn't ever accept you know, this is a good piece of advice. Because it looks clean it never is, there's always weeds in
“So, once you get convolvulus you'll have a problem with it, you've got to dig all of it out and every time you dig it out, it breaks and then it goes off in a different direction.
“The best thing to do is to go to the garden centre or an agricultural supply place and get the strongest of the systemic herbicides. “
Although herbicides will kill the plant, they will also kill anything else around the root system, she says.
Before the warm weather ends, what can we still plant?
“I would recommend that anyone who can grow vegetable garden get one in, because we're going to see some real intense increases in vegetable prices over the next few months, just because of the amount of cropping land that's been lost.
“But also a lot of the crops that were in the ground have been contaminated and will have to be removed from market gardens.”
Grow absolutely anything you can, she says.
“It's not too late to squeeze in the last crop of potatoes anywhere, that doesn't have heavy winter frost, you can get away with an autumn crop of potatoes.
“You can still be planting your brassicas like broccoli and cauliflower, lots of salad greens, but all the simple stuff, carrots,
“Anything that goes into the soil that may have been contaminated in these floods is going to be short supply. So just grow whatever you can.”
And don't even worry about buying seed potatoes just use store-bought potatoes, she says.
And flowers to lift the soul shouldn’t be ignored, she says.
“If your garden has been completely trashed by all this weather and you're giving up and you feel disheartened, just go and buy some pots and get some potting mix and get yourself some cheer.
“Buy things that take your fancy, buy plants with scented foliage, rose bushes, dahlias, things that are looking cheerful, plant those up and try to give yourself a bit of a pick me up. “
Post flooding silt need not necessarily be the gardener’s enemy, she says
“If you've got a lot of silt in your garden, rather than trying to get that out, add to it with compost, so go and use store-bought compost and start making as much compost as you can.
“If you're chopping things back, maybe hire a mulcher and make your own mulch and get that back into the soil as well and just try to improve the soil where it's been damaged.”
Photo: RNZ/Sally Round
What can I do with feijoas that took a big lean in the cyclone wind and are resisting being coached upright?
The good thing about that is feijoas can be pruned hard. You could let that just stay on the lean, until you've harvested the fruit and then prune them back really hard, you can almost prune them to the ground and feijoas will come away again.
“So, you could prune it back by say two thirds and then the new growth will all be upright. So, it's an easy fix.”
Mildew on the north island is a big issue, she says
“I think this is probably the worst tomato season for most of the North Island in living history, because of the fact that we've had so much rain and now everything's getting blight and powdery mildew as well.
“So I'm noticing a lot of powdery mildew and one of the problems is that if you're not going to be consistently spraying with a fungicide, and I personally don't agree with that. You're gonna have problems with fungus.
“And so, you might have to cut your losses and start planting more autumn things.”