Tuesday, January 25, 2011

Little bottlers of shrubs

When I was first learning gardening there were about five shrubs you would be able to guarantee most New Zealand gardens would contain – a lemon tree, a Photinia ‘Red Robin’, the ubiquitous Daphne odora, a purple Ake ake, Dodonaea viscosa 'Purpurea' and the glorious bright red Australian bottlebrush, Callistemon citrinus ‘Splendens’.
The others all had their good points, but it was the bottlebrush, hanging over our fence line from the neighbours, that intrigued me, with its flaming red flowers, usually covered with bees, and then it’s strange small nut-like seed capsules hanging grimly to the gently decumbent branches, their maturation seemingly taking years.  What fun it was for my brothers and I to roughly strip these seedpods off and throw them at each other, and other neighbourhood kids!
The common name for this popular and hardy shrub derives from its floral pattern – a bunch of bright stamen that spring outwards from the entire circumference of the branches holding them, giving a cylindrical flower that puts on an amazing floral display each spring.
The most commonly grown bottlebrushes are generally members of the Callistemon genus, although that can be misleading, as some botanists like to put all these into the wider Melaleuca genus, which also has many botttlebrushed flowers.  There are about 35 species of Callistemon in Australia, members of the wider Myrtle family that includes obvious relatives like Australia gums and New Zealand pohutukawas.   They are usually found in the eastern states, and generally grow in quite moist areas, so are best grown in similar conditions in New Zealand gardens.
The old ‘Splendens’ variety that I knew so  well is still available, and is good if you have a big shrubbery, and if you like tending your plants a little.  If left to its own devises the shrub will grow into a small tree, with a rather ungainly habit – the bottom will open up and the branches will all hang awkwardly.  On the other hand, if you prune it regularly, you will have a compact growing shrub that will take many years to reach two metres, and will reward you with a spectacular show in the spring.
Perhaps the best known variety in New Zealand today is the much smaller growing ‘Little John’.  This is a hybrid of C. viminalis, the other parent being unknown, and features lovely blue-green foliage and deep red flowers.  The flowers can be relied on to bloom for Christmas each year.
Red is not the only colour available in these reliable Australian shrubs – colours range from white through yellowish-green, mauve and pink.  ‘Reeve’s Pink’ is quite a popular variety, perhaps not quite as hardy as the two above, but still perfectly fine in a warm spot in our climate.  Even better, in my opinion, is a seedling raised from ‘Reeve’s Pink’ – ‘Mauve Mist’, which was selected from about 300 that were raised.  It forms a dense shrub to a height of about two meters with an equal or slightly wider spread. The new tip growth is pink and densely covered with silky hairs and the flowers, which are produced in usual  botttlebrush  fashion, are pinkish mauve and about 70mm long by about 50mm wide and will be carried as late as Christmas.
Among other forms available in New Zealand are the pink ‘John Mashlan’, which can be planted as a low hedge if kept trimmed; ‘Kings Park Special’ which is another bright red form and very hardy; ‘Captain Cook’; which has orange/red flowers, and ‘Rocky Rambler’ which is a new semi-prostrate form with smaller light green leaves and reduced flowers.
Perhaps the most unusual variety is one released a couple of years ago and heavily promoted as a hedge plant – ‘Great Balls of Fire’.  Despite its name, it does not have red flowers, the bottlebrushes being white in this case, but it is primarily marketed as a great hedging plant, mainly grown for the extremely pretty flush of pink when the foliage is new.

Sunday, January 09, 2011

Favourite foaming flowers

When we come to planning our flower gardens we often pay a lot of attention to the various colours we want to use, but do not give so much thought to the role texture can play, and how important the form of foliage and flower is.
The solid blocks of colour offered by most bedding plants stand at one extreme of the range of floral effects - the bright gold, yellow and orange shades of marigolds might be very appropriate in some places but hideously out of place in others – while the lighter effect of foamier flowers are at the opposite end of the scale.
At the moment the Head Gardener has a couple of plants of one of my favourite of these flowers out in her shaded garden at the moment – some two meter high examples of the glorious meadow rue, Thalictrum delavayi.   This is one of over 100 species of Thalictrum found in the wild – no-one seems to be quite sure exactly sure how many species there are, and the boundaries between species are poorly understood. They are not related to the true rues, but are members of the buttercup family, and mainly found in damp and areas.  The forms most commonly grown in the garden hail from meadowland and prefer garden soils that are on the heavy side.
They are a bit of a conundrum really, as they tend to have very dainty foliage – maidenhair fern-like in many species – which might lead the gardener to think they are frail, but they are remarkably hardy plants.  They flower late in the season and thus add colour to the woodland garden at a time when it is slightly bereft of interest.
The Head Gardener’s plants give a run of drama through the spring and early summer as they prepare to flower.  Over the winter they die down to become totally dormant.  Early spring sees them kick into life again; forming a clump of fine ‘maidenhair’ foliage from which the flower stalks will eventually emerge.  These shoot up and branch as they go until they form a graceful framework. The flower buds are to be found at the end of each of these branches.  At first green and in little clusters, they eventually turn lilac and strike out on their own, each  unfolding to become a perfect lilac parasol, with creamy white anthers dangling from pendulous stamens.
The double form of the species, ‘Hewitt’s Double’, has some of the showiest flowers any of the meadow rues, carrying its tight, pompom-like clusters of lilac-mauve flowers atop wiry, purple tinted stems.  There is also a pretty single white flowered form of this species, but I think the mauves are the best ones to go for.
Thalictrum aquiegiifolium is earlier flowering, with thousands of heads of tiny blooms that make a fluffy head of soft mauve in nearly summer, while T. flavum has pale yellow flowers..

These plants are all easily grown.  Any good soil will do, preferably in a sunny position or in dappled shade. They need adequate drainage, as a site that is waterlogged, even for part of the year, may prove fatal.
The natural tiered shape of the Thalictrum is spoilt by heavy staking. It is important to allow them to be themselves. Give them the protection of a more substantial neighbour on their windward side and plant them among other herbaceous plants that can lend a shoulder to lean on.  If you do need to stake them try to use as thin and unobtrusive a stake as you can.