Let us mulch

Canterbury and the eastern side of New Zealand is in a drought and many gardens are suffering. Mulching is one easy and effective way to conserve moisture in the soil and add nutrients at the same time.

Mulching is one of those gardening activities that is often written and spoken about but not practised enough. It makes you wonder where all our knowledge and learning is leading us. Modern chemicals, artificial fertilisers, push hoes and fascination for complete neatness and tidiness has led us away from nature and natural processes.

However, don't blame the gardeners, authors and nurserymen. The large national and international companies advertise their latest product in such a way that people think that the use of these modern marvels of gardening (weed sprays, new tools, fertilisers of all sorts, watering systems and pest and disease sprays) is the only way to cope with making gardening easy. 

Don't forget also that you probably have to look at a sterile garden and listen in vain for the birds.

Mulch is an organic substance applied to the surface of the soil to perform the following functions.

•  Adds organic matter to the soil for nutritional purposes
•  Covers the ground to prevent weed growth
•  Conserves soil moisture in summer to save lots of watering
•  Protects the soil from compaction from rain and footsteps
•  As it rots down to humus it improves the soil structure.
•  Provides an environment for developing a living  soil
•  Saves hours of work, weeding, spraying and tidying up 

Mulches can be various products and compost is the best. But there are other products that can be applied, sawdust, bark, wood chip, grass clippings, pea straw, straw, leaves etc. Rotted, well made compost has a balance of nutrients in it because a variety of organic materials were used to make the compost. 

However, do not let the lack of available compost deter you from applying organic substances as mulch. Properly managed individual products are an adequate mulch and provide the advantages of mulching with compost. Always leave these products on top of the spoil to rot down naturally.

Compost can be applied at regular intervals to the soil surface in layers up to 25mm thick. This is particularly good in the vegetable garden and in the flower garden where small plants or a show garden area is required.

Mulch should be placed on the surface between trees, shrubs and plants and over the top of areas where bulbs and perennials grow. Up to 100mm of raw uncomposted material can be laid on the ground. Generally, this is applied in spring but can be done at other times of the year except in very dry conditions.

This material will slowly rot down, but not all at once. The decomposition primarily occurs in contact with the soil. This is a thin layer. The rest on top acts as a protective layer to conserve moisture, protect the soil beneath and smother weeds. Often comment is made about "nitrogen lock up" when raw material, particularly sawdust, is applied to the soil. This is not true as only a thin layer is decomposing at any point in time. 

A garden regularly mulched over a number of years will be healthier and the plants will grow extremely well. The soil is healthy, soft and friable making it very easy to dig when planting new plants.

The use of mulches has a positive effect on the well being of all plants. Increased health, vigour, pest and disease resistance, flowering and seed production. Soil becomes healthier and brings the garden into a balance of nature. This leaves a lot of extra time for those enjoyable tasks of picking flowers, photography and entertaining.

Towards Sustainable Gardening

People are talking about sustainability all the time and it seems to be a catchword for a lot of things. Like all similar concepts sustainability only means something to people if you can actually do something. It is time we started to describe some techniques and actions people can take to move our gardens towards a sustainable garden.

In the last article we looked at planting types of plants that will grow in dryer areas. Taking that a step further we can choose a variety of plants for ordinary gardens that do not need as much water as some of our traditional plants. Choosing plants that like dryer conditions means less water usage therefore saving a little freshwater for other purposes. If everyone did this we could save an awful lot of fresh water.

Choosing New Zealand native plants for your garden is often expressed as sustainable. There is no doubt that choosing the right NZ native plants for your particular garden situation is the right thing to do and they will grow exceedingly well. However in NZ we have access to many other plants that will grow well and achieve similar goals. In choosing native plants or exotic plants always ask yourself "... is this the right plant for this place?"

Lawns. Again a water saving tip is to cut the lawns a little longer than we traditionally have done in NZ. We followed the English tradition of short fine lawns that need plenty of water. Cutting them longer, up to 5cm, will mean the lawn will stay greener longer without any watering. In California it is an offence to cut your lawns really short in order to save water. The benefit of a greener lawn for less work (and less money if you have to pay for water) is matched by a less weedy lawn as the grass will choke out lawns weeds.

Mulching provides many benefits to a garden. Firstly it will add nutrients to the soil, secondly it will help retain soil moisture by covering up the soil, Thirdly mulch is usually organic matter that has been processed rather than taken to a landfill. Mulch provides multiple sustainability benefits in gardening.

Composting at home also helps achieve sustainability. Preparing a compost heap is not at all hard. By composting our garden rubbish, weeds and prunings, we have no need to take them to a landfill, and when composted make a great mulch or additive to the vegetable garden which will promote further healthy plant growth.

Growing your own vegetables also helps our environment. With fresh home grown vegetables you will eat better. Not only that there are overall savings in transport costs, fertiliser, fuel, and insecticides.

Probably one of the most talked about subjects is the use of insecticides and fungicides. Both types of chemicals are indiscriminate and kill both the good and bad insects and fungi. This debate resulted in the organic growing movement becoming well respected. Today organic foods command a price premium over non organic foods. Reducing or eliminating these chemicals in the home garden is easy. One of the keys to reducing these chemicals is healthy plant growth stimulated by healthy soil. Healthy soils are created by adding good compost to the soil.

Sustainability does not occur in isolation. Various elements are interrelated to others. For gardening there are three key areas to concentrate on, the soil, plant choice and reduction in the use of chemicals. Spending some time adjusting these and working out the interrelationships in your own garden will help move towards a sustainable garden.

Microclimates in the garden

One of the more interesting aspects of gardening is the identification of areas in the garden which have different climates. In these locations, we can grow plants that may be different from those of our neighbours and friends. Identifying microclimates also allows gardeners to plan their garden for the best results.

To understand microclimates is to understand your garden, its orientation, soils, slope (if any), shelter, setting of the house, buildings, and anything else that directly affects the site. Gardeners also need to understand the microclimates of rainfall, sunshine hours, prevailing winds, wind types, temperature variation and the like. It is the combination of these factors which creates microclimates in the garden. Every garden has microclimates.

Soil. Soils vary greatly. Fine, clayey soils have the ability to be highly fertile, but they are also wet soils hard to cultivate and slow to warm up in spring. Sandy soils on the other hand are easy to cultivate, low in fertility and fast to warm up in the spring. Know which soils you have, what their attributes and weaknesses are and use that to advantage.

Sun. The amount of sunshine that reaches the garden will be an influencing factor. This will determine where sun loving and shade loving plants will be grown. It may also dictate the style of gardening and garden design.

In home gardens sun plays an important part in the temperature of the microclimate. Areas of the garden on the north side of a building (house) will be considerably warmer as both the soil and building heat up during the day and release the heat slowly at night. These are often frost-free areas that can be used to advantage. This phenomenon varies around buildings as each side faces a different direction each receiving more or less sun than another. Different exterior finishes on buildings also affect this.

Shelter. There are several ways parts of the garden can receive shelter. Fencing and similar structures provide shelter from wind - both warm winds and cold winds. Many plants grow a lot better without the constant battering by wind. However some gardens may have to be designed to cope with wind and good plant selection is needed in these situations.

Large trees also provide shelter from sun and frost. Even deciduous trees provide shelter so that half-hardy plants can be grown under them. Manmade such as pergolas, roofs, glasshouses and house eaves can also provide shelter from extreme conditions.

Contours. Land contours are important as they affect airflow. Cold air is heavier and will roll down a slope and congregate at the bottom where cold, cool and often wet conditions exist. It will be possible to grow different types of plants at the bottom of the slope from those grown at the top of the slope.

Identifying microclimates for a brand new garden is much more difficult as there are a limited number of factors on the section to influence microclimates. As shelter is added, suntraps created, soil modified and plants grow there is more opportunity to identify and create microclimates around the home. In more developed gardens it is much easier to identify microclimates.

Deliberately creating microclimates requires the adjustments of the factors (soil, shelter, contours, sun etc) to create the right microclimatic conditions that are required in the garden. Understanding the basics means that adjustments are easier to make to create a desired microclimate. The interaction of all these factors may be necessary for some microclimates but others may only adjustments of one or two.

Creating and using microclimates helps gardeners create the type and style of garden that they want.

Snow business

Gardens covered in snow are everyone’s fairytale dream. We see movies about Christmas with snow falling gently on the garden and trees. It’s romantic. It’s fun. It’s cosy inside.

Out in the garden though snow can cause a few problems.

Let’s firstly dissolve one myth. Snow is cold and the cold snow will harm plants. This is not true. Snow by itself is at freezing point or just a little below that and it does not get any colder. In the mountains snow acts as a sort of thermal layer between the really cold stuff - frost, ice and icy wind. The alpine plants love it under snow. They are protected from the real cold and survive very nicely. In spring when the snow melts they get watered as well.

Cold is a bad thing for some plants but the really harmful cold is frost and ice and icy wind. Tender plants from warmer climates do not have tough outer layers for protection from the cold and ice. The damage to these plants is caused by water inside the individual plant cells freezing. When water freezes it expands. When water inside a plant cell freezes and expands the cell tissue is destroyed. Have a look at tender plants after a frost and notice that the leaves will turn black very quickly that day and the leaves, or stems or both will die.

Protection of plants from frost damage is usually provided by covering the plant/s with a layer that will stop the frost from getting to the leaves. There are products on the market that can provide this sort of protection but in early years sacks, frost cloth and other material was used very successfully.

So what damage does snow cause?

The biggest and most notable amount of damage caused to plants by snow is breakage. It is the weight of snow sitting on a branch or branchlets that cause them to break. Branches are only used to carrying leaves not the weight of snow.

Throughout Canterbury many, many trees have been damaged by branches laden with snow and then breaking under the strain.

To prevent the loss of branches the best thing to do is to remove the snow. This can be done by shaking smaller trees and shrubs to get the snow to fall off.

Another method for larger plants would be to hose them down with cold water from the hose. The water may freeze but that will not cause a great deal of harm to the plant. For many years the apricot growers in Central Otago used a water spray to cover their orchards when frost was forming. This was because when water freezes it actually gives off latent heat and the temperature does not drop much below freezing point. However a frost can take temperatures well down below freezing point and destroy cell structures.

Broken branches are a major snow damage problem. There is little that can be done when the branch is broken. Preventative action like removing snow is important.

Once a branch is broken there is little that can be done to repair it. Therefore careful pruning is required to remove the branch. Sometimes complete removal is necessary but other times only the broken piece needs to be removed. When removing the branch cut it back to a branch join to avoid stubs.

If branches are split along the branch removal of the weight of snow is critical. Split branches may repair themselves with a little permanent help. Take some of the branch weight off by trimming the branchlets back. Attach a wire from the split branch to a solid branch and tighten it up until the split is closed. Leave the wire in place in the tree for the rest of its life as the branch will be a lot weaker.

Falling and settling snow is a lovely thing but can cause damage to plants. To prevent major damage to important trees and shrubs remove the snow by shaking the  plant or using cold water from the hose.

Garden hygiene

Many times I have written these words, Garden Hygiene, as part of gardening activities, but what does it mean?

It is really quite simple; it's a bit like housework in the garden.

Where there is some form of infestation by insects, fungi or bacteria remove infested material, leaves, spent flowers and prunings and dispose of them through the rubbish or if allowed by burning. Only put in the compost if you have a very hot compost heap with temperatures up to 70C.

Ensure weeds, which harbour breeding colonies of insects, are removed and replaced with ornamental or edible plants.

Clean all garden tools straight after handling infested material to stop infection spreading around the garden.

Do not shift infected soil around the garden or transplant infected plants from one part of the garden to another. If plants are suffering from infestations of pests and diseases maybe the plant should be shifted to a new position better suited to the plant and less suited to the pest or disease but care is suggested and the plant treated to rid the problem.

Give plants a little air by pruning them back and thinning out dense plants. It is in these dense conditions pest and diseases flourish as they find a nice cozy little home to live and multiply in. One example often given is that camellias should be pruned and thinned so that a blackbird can fly through it.

Stop overcrowding of vegetable plants and ornamentals. Experiment with the best distance to plant vegetable plants apart to give the best crop as possible.

Keep this up regularly throughout the year.

Good garden hygiene is the basis of a healthy garden which in turn leads to lower maintenance and more enjoyment of the garden.

Snow business

Gardens covered in snow are everyone’s fairytale dream. We see movies about Christmas with snow falling gently on the garden and trees. It’s romantic. It’s fun. It’s cosy inside.

Out in the garden though snow can cause a few problems.

Let’s firstly dissolve one myth. Snow is cold and the cold snow will harm plants. This is not true. Snow by itself is at freezing point or just a little below that and it does not get any colder. In the mountains snow acts as a sort of thermal layer between the really cold stuff frost, ice and icy wind. The alpine plants love it under snow. They are protected from the real cold and survive very nicely. In spring when the snow melts they get watered as well.

Cold is a bad thing for some plants but the really harmful cold is frost and ice and icy wind. Tender plants from warmer climates do not have outer layers for protection from the cold and ice. The damage to these plants is caused by water inside the individual plant cells freezing. When water freezes it expands. When water inside a plant cell freezes and expands the cell tissue is destroyed. Have a look at tender plants after a frost and notice that the leaves will turn black very quickly that day and the leaves, or stems or both will die.

Protection of plants from frost damage is usually provided by covering the plant/s with a layer that will stop the frost from getting to the leaves. There are products on the market that can provide this sort of protection but in early years sacks and other material was used very successfully.

So what damage does snow cause?

The biggest and most notable amount of damage caused to plants by snow is breakage. It is the weight of snow sitting on a branch or branchlets that cause them to break. Branches are only used to carrying leaves not the weight of snow.

Throughout Canterbury this winter many, many trees have been damaged by branches laden with snow and then breaking under the strain.

To prevent the loss of branches the best thing to do is to remove the snow. This can be done by shaking smaller trees and shrubs to get the snow to fall off.

Another method for larger plants would be to hose them down with cold water from the hose. The water may freeze but that will not cause a great deal of harm to the plant. For many years the apricot growers in Central Otago used a water spray to cover their orchards when frost was forming. This was because when water freezes it actually gives off latent heat and the temperature does not drop much below freezing point. However a frost can take temperatures well down below freezing point and destroy cell structures.

Broken branches are a major snow damage problem. There is little that can be done when the branch is broken. Preventative action like removing snow is important.

Broken branches are a problem. Once a branch is broken there is little that can be done to repair it. Therefore careful pruning is required to remove the branch. Sometime complete removal is necessary other time only the broken piece needs to be removed. When removing cut back to a branch join to avoid stubs.

If branches a r split along the branch removal of the weight of snow is critical. Split branches may repair themselves with a little permanent help. Take some of the branch weight off by trimming the branchlets back. Attach a wire from the split branch to a solid branch and tighten it up until the split is closed. Leave the wire in place in the tree for the rest of its life as the branch will be a lot weaker.

Falling and settling snow is a lovely thing but can cause damage to plants. To prevent major damage  to important trees and shrubs remove the snow by shaking the  plant or using cold water from the hose. 

How to Shift Plants around the Garden

The cooler winter months are excellent to shift plants around your garden or give them away to your friends for their garden.  This is a great job and lots of fun especially if you change your mind.

As part of your garden planning you will identify plants that should be placed elsewhere for best effect. Take several walks around the garden and think about the positions you would like to change.

One of the rules of planting is “right plant right place”. Make sure that the plants you want to shift are going to be placed in the right location in the garden that suits the plant. Shade loving plants in shaded places and sun loving where they will get a lot of sun.

Shifting plants

• Identify where you want to position the plant and prepare a planting hole
• The new hole should be two (2) times as wide as the proposed root ball and the bottom of the hole forked up so the soil is loose.
• The plant to be shifted can be pruned to a desirable shape. It is important to reduce the top of the plant back to match the amount of roots that are going to be cut when the roots are dug up and cut through. Reduce by about one third.
• To identify where to insert the spade, work out this mathematical problem. Measure diameter of stem, multiply that by two (2) and add on the width of your spade.
•  Dig a trench around the plant undercutting the roots to create a root ball of soil and water.
• Carefully loosen the plant by moving the plant from side to side or getting spade right underneath it and lifting it up
• Carefully work a strong tarpaulin or similar under the root ball and lift the plant out of the hole by lifting the tarpaulin etc.
• At the new hole place the plant in position in the hole so that the depth of the root ball is the same as in its previous position
• Once in position carefully backfill the hole making sure the soil goes right down around the roots.  Firm the soil down to ensure the plant is held in position firmly. The soil level around the plant must be the same as in its previous position.
• If it is a tall plant stake it well so that the winter winds will not blow it over. 
• Water well and mulch the surface.

Trees for Bees

The honey bee is one of the world’s hardest workers. In NZ bees about $3billion of GDP is directly attributable to the intensive pollination of horticultural and agricultural crops. They also contribute indirectly by pollinating clover which is ten sown into our farm land to grow better fodder for animal food.

Of all the food we eat about one third of the calories and three quarters of our biodiversity rely on bees for pollination.

Throughout the world bees are in trouble. Bees are being attacked by pests (e.g . varroa mite) and diseases. Also many of the traditional flowers from which bees collect pollen and nectar are in decline.

One constructive way to help bees is to plant a variety of trees and shrubs that provide food for the bees.

Below are two lists of plants, shrubs and trees suitable for South Island conditions here in New Zealand. The first is a list on NZ native plants and the second is imported plants. There are different sized and shaped plants for different situations. Choose some to plant at your place in or other public or private areas.

Native plants are the best choice to increase native biodiversity and benefit both the honey bee and the environment.  

Cabbage tree (Cordyline australis) --- Tree, 15m, Oct-Dec

Five-finger (Pseudopanax arboreus) --- Tree, 8m, Jun-Aug

Hebe  (Hebe spp.  e.g., gracillima) --- Shrubs

Horoeka (Pseudopanax crassifolius) --- Tree, -6m 

Kānuka (Kunzea ericoides) --- Tree/Shrub, 15m, Sep-Feb

Karangū (Coprosma lucida) --- Tree/Shrub, 4m

Kohuhu (Pittosporum tenuifolium) --- Tree, 6m, Oct-Jan

Koromiko (Hebe salicifolia) --- Shrub, 3m, Jan-Feb-(Apr)

Lemonwood (Pittosporum eugenioides) --- Tree, 10m, Oct-Dec

Manuka (Leptospermum scoparium) - Tree/Shrub, 5m, Sep-Mar

Matagouri (Discaria toumatou) --- Tree/Shrub, 5m, Oct-Jan

Narrow-lv lacebark (Hoheria angustifolia) --- Tree, 10m, Dec-Mar

NZ flax (Phormium tenax) --- Tufted, up to 5m flw. stalk, Nov-Dec

Ngaio (Myoporum laetum) --- Tree/Shrub, 8m, Jul-Apr

North Island broom (Carmichaelia australis) --- Shrub, 2m, Oct-Feb

Pink tree broom (Carmichaelia glabrescens) --- Shrub, 3m, Dec

Scented broom (Carmichaelia odorata) --- Shrub, 3m

South Island broom (Carmichaelia arborea) --- Tree/Shrub, 3m

Sth. Rata (Metrosideros umbellata) --- Tree/Shrub, 15m, Nov-Jan

Tree fuchsia (Fuchsia excorticata) --- Tree/Shrub, 12m, Jun-Jan

Weeping kowhai (Sophora microphylla) --- Tree, 10m

Exotic plants are good choices because many are multi-purpose and have excellent pollen and nectar.

Apple (Malus ×domestica) --- Tree, Sep-Nov

Bottlebrush (Callistemon splendens) --- Shrub, 2m, Oct

Grevillea (Grevillea spp. e.g., ‘Clearview David’, or ‘Victoria’)

Horse chestnut (Aesculus hippocastanum) - Tree, 36m,Oct-Nov

Lavender (Lavandula stoechas) --- Shrub, 1m, Sept-Dec

Pear (Pyrus communis) --- Tree, Sep-Oct

Rosemary (Rosmarinus officinalis) --- Shrub, 1.5m, Sep-Nov

Tree lucerne (Chamaecytisus palmensis) Tree, 5m, May-Oct

Blue gum (Eucalyptus globulus) --- Tree, 40m, Sept-Dec

Ribbon gum (Eucalyptus viminalis) --- Tree, 40m, Jul-Apr

Silver dollar gum (Eucalyptus cinerea) --- Tree, 15m, Dec-Feb

Snow gum (E. pauciflora subsp. niphophila) --- Tree, 18m, Sep-Nov

Swamp peppermint (Eucalyptus rodwayi) --- Tree, 15m, Mar-Jun

White ironbark (Eucalyptus leucoxylon) --- Tree, 30m, Mar-Nov

Yellow box (Eucalyptus melliodora) --- Tree, 30m, Dec-Feb

Weeping Willow (Salix babylonica) --- Tree, 25m, Aug-Sep

http://fedfarm.org.nz/f1759,65241/65241_New_S4_Canterbury.pdf

Material for this article was taken from Federated farmers brochures and website.

July in the Garden 2010

here is a link to what to do in your garden in July


July in the Garden 2010

Hope you enjoy this and if you have any suggestions for gardening in NZ in July please let me know by leaving a comment.

happy Gardening

Alan

Pruning demonstration

Pruning demonstration

Saturday 14 August
9.30am – 11.30am Mona Vale Gardens
Fendalton Christchurch 
Open to the public free

Growing out of the Recession.

2008 and 2009 were years many people would like to forget and fortunately 2010 looks like it will be better. Things are still tough and it will take some time to be really bright again.

We may be able to help others this year. Some of the things we can do individually, as small groups or as a large group may be to

• Take a bunch of Garden flowers to someone you know needs a lift.
• Give away some surplus vegetables grown in your garden to someone not as well off as ourselves.
• Help someone establish a new vegetable garden
• Give away some surplus plants to help brighten up another person’s garden
• Take a bottle of homemade jam, chutney or other produce to a neighbour
• Give a one year membership to a garden club or similar to a deserving person or family
• Introduce them to Blotanical and the internet

All these acts of kindness, and others I have not thought about, will show we live in a community that cares. The community can lead the way in brightening up peoples lives by sharing our gardens with them.

There is a great little saying “Give a man a fish and he can eat for a day, teach him to fish and he can feed himself forever” maybe we should have one that says “Give a person food and they can eat today, teach them to garden and they can feed themselves and others forever.”

In this respect bloggers can lead the way us sharing our knowledge and teaching others how to garden, groups of gardeners can get together and learn more 

Let us start this year in such a way that we can and will make a difference in peoples lives.