Imagine moody, cloud-covered mountains, the slopes covered with native conifers and beech forests, lowland forests of Kahikatea and Puketea stretching down to swamps, sandy beaches and plains. That was New Zealand before people arrived - mountainous, temperate, lush and damp. That is the foundation of our soils here and the starting point for gardens in our country.  When you start planting a new garden in New Zealand you are at the mercy of the climate, the underlying soil, and what has been there before. 

 

River stones surrounded all the plants in the gardens at my house in Cambridge when we moved in last year. YIKES!! I thought. Seven months later, as I finished removing the last round grey horror, both the soil and I breathed sighs of relief. Phew, now we can start making the soil really pop. After all, everything in your garden depends on it, although many take it for granted...after all, it's just dirt, isn't it???

Well actually, the soil and its condition can have a big influence on what you can grow and how well it thrives. It may surprise you to learn that soil is made up of 25% air and 25% water combined with 45% inorganic material. It's this inorganic material - basically ground-up rocks - which dictates what the characteristics of your soil will be and it comes down to three different types: sand, silt and clay. Clay soils tend to dry out in summer, be wet and have poor drainage in winter, but can be rich in nutrients. Sandy soils will be free draining, but can't hold water in summer, they are often low in nutrients and warm up quickly in the spring. Silt soils are in the middle, with reasonable drainage and nutrients. These last are usually the soils found in river valleys and alluvial plains.

The best thing you can do for your soil, whatever its makeup and whichever plants are in it, is to add organic matter. You can't change the basis of the inorganic part which comes from the rocks underneath, but that tiny 5% of the soil which is all the 'once living, now dead stuff' makes a massive difference to the nutrients it contains and can help hold water in the summer time when moisture is in short supply. Dead stuff = compost, fallen leaves, flowers, sticks, worm castings, dead bugs and animals and it's all this dead stuff which the worms and other creepy crawlies use to create the lovely rich dark organic matter we call humus (not hummus, which is chickpea dip!). So the first thing I did when the river stones came off was to add a thick layer of wood mulch. It's a great moisture retainer, adds organic matter as it breaks down and stops weeds germinating. Win, win, win.

   

Another key feature of any soil is its pH. This is a measure of how acidic the soil is and usually can be traced back to the underlying parent rock, the climate and what has been growing there. If it's been a paddock previously then over time the soil probably has become more acidic, or if was a peat bog or once a conifer forest (think Rimu, Totara, Kahikatea) then it will also have higher acidity. New Zealand soils tend to be on the acidic side with most being between 5.0 and 6.5 on the pH scale (0-14 with 7 being neutral, and anything below 7 being acidic while anything above 7 is basic). Luckily there are many plants which thrive in acidic soils. I will talk about some of these below...

These are a stunning group of plants which are closely related to the Magnolias (also acid loving). In fact there is some debate about some of the new Michelias which have been named "Fairy Magnolias" but bear a lot of similarities with the Michelias. These evergreen beauties have a lot of the advantages of Magnolias with a few extra and we stock three of them:  Magnolia Fairy Cream, Fairy Blush and Fairy White. 

 

Michelias and evergreen fairy Magnolias share several advantages over deciduous Magnolias; here are four of them. 1) The fairy Magnolias are a bit smaller growing than their Magnolia grandiflora cousins (on our website as Magnolia ferruginea); think 2-4 metres as opposed to 5+ metres. 2) They often have fragrant flowers - we have several gorgeous Michelia maudiae down by our lake at the nursery which are stunning with creamy white flowers which fill the air with their delicious scent. Many of the other Michelia varieties e.g. Figo, Bubbles, Mixed up Miss, Yunnanensis are fragrant too; 3) They can easily be made into hedges, standards and other shapes to suit. This is mainly because the leaves and internodes (space between leaves) are smaller than those of the larger varieties, giving a tidy and neat appearance when cut. The Port wine Magnolia (Michelia figo) has long been favoured as a shade tolerant hedge or pretty standard. 4) They can flower multiple times a year and the flowers are in clusters rather than one at the end of each stem. All in all, they are a valuable group to plant. 

 

In the same vein as New Zealand soils, many parts of Asia (e.g. Japan) have been subject to volcanic activity and high rainfall which has resulted in acidic soils in which Rhododendrons and Azaleas have thrived. These are another pair of closely related plant groups which could be called cousins, as they have many similarities but some important differences. Rhododendrons are evergreen and have bell shaped flowers. They can grow different heights from dwarf Under 1m e.g. Doc, Apple Brandy, Baden Baden, to large shrubs like Sappho, Anna Rose Whitney, Black Sport and Mount Everest.

 

As for the Azaleas...I have talked about Deciduous Azaleas recently but there are also Evergreen varieties. The main difference between rhododendrons and evergreen azaleas is that the latter tend to be more compact and the flowers are funnel shaped where the petals are fused together. There are loads of colours in these too. If you are on site you can check out our gorgeous Azalea Kirin hedge in the display garden which is in flower at the moment. Other popular varieties include Kiwi Anniversary, Clarissa, Red Glitters, and Kocho No Mai.

   

There are two quite distinct plants with the common name 'Lily of the Valley'. Lily of the valley (Pieris) is a shade-tolerant, acid-loving shrub which when flowering becomes covered in showy bells of white or pink. An added feature of this shrub is the fresh red or bronze foliage which makes a striking appearance in Spring. There are variety of sizes and colours to suit your garden. This is not to be confused with the dainty bells of the perennial Lily of the Valley (Convallaria) which grows and flowers in shady areas and is a bulb. Despite their similar flower shape, the two genera are unrelated and very different.

 

STOP PRESS: Griselinia Broadway Mint. We have just received another batch of these popular hedging plants. These are a nice bushy grade and perfect for creating a medium-sized hedge. They are fast growing and tolerant of many soil conditions. They need to be watered well in the first few summers to help them establish, but beware of too much water in the Winter: Griselinia don't like having wet feet and prefer well-drained soil.

 

Currently we have the project of feeding all of our 2024 trees and shrubs with a slow release fertiliser. This helps them flush away with the warmer weather and keeps them performing well when you plant them in your garden! Don't forget to fertilise your plants at home. It's good for fertiliser to be watered-in, and it looks as though we can expect enough rain this weekend to do just that; in Hamilton anyway.

Have a great weekend, even if it is a slightly soggy one.

Cheers from Lloyd, Tony and the Wairere team.