Category Archives: Plant collector

flowering this week, tried and true plants

Plant Collector: Oxalis purpurea alba

Oxalis purpurea alba - one of the very best forms

Oxalis purpurea alba - one of the very best forms

At this time every year, I embark on a crusade to win new converts to the world of oxalis. The whole oxalis family suffers from the bad habits of just two or three members and it means that many people miss out on the seasonal delights of some of the highly ornamental forms. Purpurea alba is one of the very best. It is not in the least bit invasive and I have no problem at all in recommending it for sunny spots in the garden where it forms a flat mat of slightly hairy, clover-like foliage topped with big white flowers with a yellow throat. Where it excels above most others is in the length of its flowering season. It is one of the first to flower and continues through to pretty much the end of the season in winter.

Oxalis purpurea is a highly variable species. The red leafed form with big pink flowers comes into growth much later and is invasive. Decorative but dangerous so keep it confined to a pot. The green leafed form with big pink flowers shares a long flowering season almost on a par with alba and does not appear to be invasive. There are apparently yellow forms of this species too. Overall, there are large numbers of different oxalis. They occur in both South America and South Africa but it is the African ones which give us most of the showy varieties for garden use. Most come into growth with the autumn rains and they have to be planted in full sun because they don’t open their flowers unless it is sunny. They make a wonderful show in shallow containers on a sunny doorstep and you can always refer to them euphemistically as wood sorrel, if you don’t want to own up to growing oxalis.

Plant Collector – Camellia sinensis

Grown to harvest for tea, rather than its floral display - Camellia sinensis

Grown to harvest for tea, rather than its floral display - Camellia sinensis

Despite being one of the first camellias of the season to flower, Camellia sinensis is not grown for its floral display but as a crop. It is the tea camellia. All tea comes from the same plant. Whether it is green tea, oolong tea or black tea depends not on the plant variety but on how it is dried, fermented and roasted. The preparation of quality teas takes a skill level on a par with roasting coffee or making wine. You can, however, harvest easily for home consumption, unlike wine and coffee. Green tea is unfermented and the leaves can be used fresh or dried. Oolong tea is lightly fermented (or sweated) and very lightly roasted. Further along the line is the fully fermented and roasted black tea. For the very best quality, you only pick the three leaves of fresh growth. By picking, you encourage the plant to continue pushing out fresh growth.

Camellias, as we all know, grow extremely well in New Zealand. The first attempts to grow sinensis commercially failed because of the site – cold inland valleys of Nelson. The frosts burned the desirable new growths. There is now a Taiwanese plantation near Hamilton which specialises in high quality oolong tea for the Chinese market. Most C. sinensis flower white. This form has flowers in dusky pink, but still tiny. The leaves are not like a common shiny japonica, being longer, crinkly and softer. We grow it in the vegetable garden and keep it to about 1.5m high x 1.2 m wide. Should Armageddon strike, we will have to drop coffee off the menu but we can still drink tea. I will just have to find out which bergamot is added in order to replicate our favourite Earl Grey tea.

Plant Collector – brugmansia

Double white brugmansia - huge, frilled white trumpets

Double white brugmansia - huge, frilled white trumpets

If you are into frills and furbelows, it is hard to go past the charm of this double flowered, pure white brugmansia. It is a member of the solanum family – as are tomatoes, capsicums, aubergines and, indeed, the dreaded woolly nightshade. None are as ornamental. The fragrant brugmansias hail from South America, mostly around Ecuador and the Andes, and are somewhat frost tender so presumably it is low altitude Andes. They are woody shrubs, around 3 metres high. This one is likely to be Brugmansia x candida (or aurea x versicolour), sometimes referred to as B. “Knightii”. We have it growing in open woodland conditions but it is also quite happy in full sun.

The differentiation between brugmansia and datura seems to be on a sliding scale. Brugmansias all used to be classified as datura. Now there is a school of thought that all datura are in fact brugmansia. What is usually referred to as a brugmansia has hanging (pendulous) flowers and woody stems whereas what are commonly called datura have horizontal or upward facing flowers and herbaceous growth. In days gone by, suicidal youths would regularly kill themselves trying for hallucinogenic experiences (now probably replaced by synthetic drugs which, while not safe, are not usually fatal). The problem is that while there are hallucinogenic properties, all parts of this plant are highly poisonous. A psychedelic trip can be a one-off experience with a high price to pay.

Plant Collector: Frangipani

The intoxicating fragrance of frangipani (or plumeria)

The intoxicating fragrance of frangipani (or plumeria)

Alas, these frangipani are not growing in our own garden. We were in Sydney last week where they are common in home gardens. We have two plants here which we have managed to get to a good size in pots and we plan to give them optimum conditions in the hottest possible, sheltered position at the front of the house because the fragrance is just to die for. I am sorry we don’t have the exotic rosy pink and yellow form, but only the more common white with a golden centre, more correctly known as Plumeria rubra var. acutifolia but frangipani will do just fine, thank you. There are dark red forms too.

Despite the fact that they are common in the Pacific islands and throughout Asia, frangipani originate from Central America (think Mexico, Venezuela and the Caribbean) and therein lies the problem – they are tropical but we are not. They are of the large deciduous shrub to small tree class, but very sappy plants so more akin to some of the larger euphorbias in growth. They will grow happily in pretty tough conditions as long as they never get cold or waterlogged.

What is often called the Australian frangipani is a totally different plant. It is an evergreen tree, usually very large though there are some smaller selections becoming available, and is in fact Hymenosporum flavum. Being a Queensland forest tree, it is not quite as tropical as plumeria but neither is it as exotic and attractive in bloom. We will keep to the plumeria and hope for that unmistakable scent of the tropics in summer.

Plant Collector: Castanospermum australe

A mission requiring the tall extension ladder - gathering the Castanospermum australe flowers

A mission requiring the tall extension ladder - gathering the Castanospermum australe flowers

It was just a little difficult to photograph the orange pea flowers on the castanopsermum, owing to the fact that they are at least 10 metres up the tree and beyond the limit of my camera’s zoom. Getting this photograph entailed Mark on the end of the extension ladder cutting a branch to bring down to ground level. The tree itself is probably getting closer to 20 metres now, though it has taken several decades to get there. I was slightly alarmed to see that it has the potential to reach 40 metres high in its natural habitat of east coast Australia, particularly Queensland, but I doubt that it will reach that in our cooler climate, or indeed in my lifetime.

The common names for this plant are Black Bean Tree (on account of its large black seeds held, as legumes are, in a pod) and Moreton Bay Chestnut. Indeed castanea means chestnut in Latin and that is where it gets its name from. It has always been much on my conscience that many years ago when we sold a few of these (and painfully slow they were, to get grown to saleable size), in my ignorance I assumed that the common name of Moreton Bay Chestnut meant the seeds were edible. They can be eaten – if you are Aboriginal and understand the painstaking process of rendering toxic seeds edible (a bit like karaka berries in this country). Lacking that knowledge, poisoning is more likely. As the tree takes some time to flower, I am hoping that my incorrect plant labels will long since have faded into oblivion so nobody tries eating the seeds.

The tree is evergreen and has handsome, pale green, large pinnate leaves – pinnate meaning divided like a feather. Should it outgrow its space here, apparently the timber is attractively grained like walnut.