Gardening: The root of the problem

It's time to lightly trim the early growth from your hedges. Photo / APN

Landscape gardener and Life columnist Justin answers your questions.

We have a karaka that we planted at the start of the year. It was doing great, but we have noticed since the heavy winds the leaves on it have started to turn yellow and are limp. In the same location we also planted a puriri and titoki which are doing great. What are we doing wrong with our karaka tree? We live in Clendon Park near the sea.
- Bevan

A karaka is not an uncommon tree to find near the sea and I doubt that the salt air would be having a detrimental effect on it. It is more likely to be wet feet, which is consistent with heavy coastal soils. Alternatively, it could be root rock, which is caused by excessive wind exposure lifting the roots, especially when trees are young.

Firstly support your young trees by staking and tying with solid supports. In really bad wind you may need to add a windbreak. Unlike the puriri and titoki you mention, the karaka does not handle wet feet well and may need to need to be lifted slightly.

It will definitely respond positively to having organic matter placed around the drip line.

A technique you may be interested in which would serve your purposes well is colonising. This means you grow more robust, faster-growing plants (pseudopanax arboreus or pittosporum) around your trees to protect them. Then, once your trees are established, you shed the less desirable plants to expose the stronger, well-established tree.

I need to remove two cypress-like conifers from near my house. They are currently about 2m tall - so still babies in the scheme of things. If possible though, I'd like to save them, for replanting, either at the back of the property or to put into big pots. What's the best way for me to dig them up so that they survive? They've been in about three years and the roots are entrenched.
-Lauri

To be straight up with you I don't think it's going to be worth your while. Conifers are very temperamental plants to transplant and for the expense, work and cost required, I think you would be better off planting some new conifers in your new spot and, unfortunately, discarding the existing ones.

But if you still want to give it a go, it's not impossible. Make sure you wrench the trees over a two- to three-month period to help reduce shock, water regularly and keep watering while they are in their new home.

Protect your transplanted conifers from the wind as this can really dry them out and the effect will quickly be terminal. Try a product like StressGuard liquid which can improve you transplantation chances no end. I hope you prove me wrong - let me know.

We seem to have been taken over by green caterpillars, from small to large. They have eaten all the iresina plants and are now moving into the vege garden. Last weekend I even found the mint devastated by them. We sprayed the iresinas for caterpillars, but it didn't seem to have any affect. Apart from removing them by hand, what else can we do?
-Irene

When you spray, make sure you spray under the foliage which is where I think you'll find the caterpillars hide. I recommend going through all the plants and removing them by hand. If you can't face this then take a bottle of wine and some nice music with you. Once the bushes are cleaned out - and this may take two or three goes - spray the plants with garden oil on the top and bottom of the leaves (I use olive oil and garden-friendly dish soap diluted in water).

To stop butterflies laying eggs on your plants set some moth traps. String squares of yellow plastic smeared with Vaseline among your plants to attract and trap the butterflies.

My old orchid is very pot-bound and for the first time hasn't produced any flowers this season. What should I do to split it and get it going again? Should I use a specialist orchid mix or is regular potting mix ok? Is now the time to do it? What and how often should I feed it?
-Katy

Your orchids are fine being pot bound, they actually prefer it.

You will probably find your orchid needs purging, as the fertiliser used to keep your orchid in long flower deposits nitrates and other elements, making the soil too acidic for your plant.

Firstly stop feeding it anything, then dry the root ball out completely. Once this is done soak the whole thing in fresh water then dry it out again. Repeat this two or three times.

If you want to re-pot the orchid or split it up, use specific orchid mix and replant it into a pot which has an open top.

Orchids are hungry so be liberal with your feeding but once the flower has finished then remember to purge it ready for the next season.

GARDENING CHECKLIST

In the vege garden:

Plan and prepare where everything will go for your spring, and even summer, garden. You can do this on a piece of paper or just by marking the ground with sticks.

Take care to include crop rotation in your plans as well as companion planting (my new book has a comprehensive guide to both, or check my earlier stories on nzherald.co.nz). Get the beds ready by either layering a good thick cake of well-rotted material on top of the beds or by digging in or trenching manure or seaweed.

Start sowing peas, beans, carrots, beets, radish, lettuce, onions; plant garlic, and brassicas. Start chitting, or sprouting, potatoes in a warm dry place. Plant strawberries and herbs like thyme, oregano and sage. Split and re-pot french tarragon.

Sow chillies and eggplant in containers. These will need to be kept in a warm place like a cold frame or hothouse until the weather warms up but it's worth getting these going early as they can take a while to bear fruit - you may even want to use a poly tunnel when you do plant them in the ground which will accelerate early development.

In the fruit garden:

If you haven't finished - or started - your pruning, then get it done now. The sap will soon be on the rise and deciduous trees and roses will be putting on a right old show. Plant fruit trees, deciduous ornamentals and roses. Getting these in the ground before the weather warms will ensure maximum growth in the first year which will give you a stronger tree overall. Remember to take care with soil preparation and stake and tie well using arboricultural ties.

In the flower garden:

Trim early growth off hedges. This is a very light trim so don't take the new growth right off, just enough for the hedge to bifurcate which will thicken up the new growth. Take care with flowering hedges. Once they start to produce flower buds it's too late, as trimming the hedge while in bud, will radically reduce flowering.

Plant flowers for spring such as begonia, snapdragon, carnation, cornflower, dianthus, stock, delphinium, alyssum, forget-me-not, larkspur, linum, lobelia, cosmos, lupin, marigold, nemesia, pansy, sweet william, celosia, petunia, phlox, zinnias, portulaca, salvia, linaria, statice, sweet peas, violas, candytuft and poppies.

In the compost bin:

Mulch all veggie beds with pea straw, all flower beds with newspaper and commercial compost and trees with tree mulch.

Remove any compost from compost bin and turn it, adding light brown material if it is too wet or fresh lawn clippings if it is too dry. As you reinstall it into the compost bin, water in each 100mm layer if the mix is too dry, then cover with polythene.