Top tips for vireya success

David Brown of Versatile Vireyas near Tauranga has some top tips for success with these tropical-look plants (in no particular order):

When planting, don’t rip the root ball apart. Vireya rhododendrons have fine, hairy roots and they need them all! “A healthy root system is too valuable to pull apart,” David says. “It’s best to leave well alone.”

Fertilise them well as they grow year-round and flower year-round (being from the equator they don’t have seasonal growth triggered by longer days). Sheep pellets are okay, but for vireyas a slow-release is probably better, apply every 6 months.

“Why rake up autumn leaves from your garden and dispose of them and then put fertiliser on the garden?,” David asks. “Let the leaves stay and the vireya roots will come up to where they should be – in the top 2 inches of the soil.”

Vireya Zeus. Photo: Sandra Simpson

You may be told at a garden centre that vireyas need only morning light or half a day of shade. Nonsense, says David. He saw them growing in tree tops in Indonesia and had a moment of clarity – vireyas happily grow in full sun and should be grown in full sun. However, he warns they won’t look as tropical as the soft leaves will harden to cope with the extra light. The plants will flower more often, but the flowers won’t last as long.

There is no need to prune, so don’t. The plants will be stronger and happier if left alone. Once a vireya has reached the optimal height to produce lots of flowers it won’t get any taller, only wider. The height varies from plant to plant.

However, if a gardener feels there is a real need to prune, feed the plant well for 3 months beforehand so it’s in full health. Prune only when the plant is in active growth (not flower growth). “I believe that when the sap is pushing through it will also move the buds along.”

David’s preference is to prune to a leaf cluster, rather than to a bud on the stem, as each leaf cluster contains a number of buds and offers more chance of new growth.

After flowering do dead-head the bush – this doesn’t mean removing the leaf cluster (there are new buds there) that the flowers have nestled in, but pulling out or clipping the spent flower heads and stalks from within the cluster (ie, leave the cluster on the branch). If you don’t dead-head the plant puts all its energy into developing seed capsules and this will set back the next flowering by 3 to 6 months.

Young plants can be tipped (pinch out the growing tip) to produce a bushier vireya.

Vireya Kisses. Photo: Sandra Simpson

Vireyas dislike lime which locks up an essential nutrient in the soil, David thought iron. Calcium is important to create strong plants and he recommended gypsum as something that doesn’t alter the soil’s pH. Sold as ClayBreaker at garden centres.

If growing vireyas in a pot, be sure to use exactly the same potting mix as in the old pot in the new container and don’t move into a much larger pot. Try not to disturb the roots.

As we’re in winter and experiencing some hard frosts, David noted that vireyas are frost tender. If covering, it’s best to have the cloth above the plant (ie, not touching the leaves) to ensure there’s no damage. “I’ve seen plants with three layers of frost cloth laid on them get burned. I prefer to use weedmat and always keep it above the plants.” For his commercial operation he has also used irrigation as a protection against frost.

Read more about vireya rhododendrons at this specialist website.

Our native plants: Mountain cottonwood

Despite its common names of mountain cottonwood or silver heather, Ozmanthus vauvilliersii (formerly Cassinia vauvilliersii and also known as Ozothamnus leptophyllus) is found all over the place – my photo was taken on the walk from Eastbourne to Pencarrow lighthouse with the plant growing either side of the track which, for the first hour at least, is right beside Wellington Harbour.

The Hebe Society (based in the UK) lists it and I was certainly wondering if it was a hebe as I looked at it, something about the compact leaves. It’s almost redundant to say it copes with harsh conditions and copes with everything from snow to salt-spray (the track would easily be inundated in a good blow). A good plant for a dry garden.

Mountain cottonwood flowers from December to April, but this plant was photographed in July and had buds on it, as well as spent flower heads. Photo: Sandra Simpson.

In his book The Cultivation of New Zealand Trees and Shrubs (Raupo, 2011) Lawrie Metcalf says: “Five former species within the genus Cassinia, now reclassified as Ozmanthus, are so variable and have so few distinguishing characters that there has been a tendency to regard all of them as simply variants of just one species, O. leptophyllus … All parts of the shrub, including the flowers, have quite a strong scent.”

Known by Maori as tauhinu, the shrub is, Metcalf says, a good nurse plant for more tender, permanent plantings (just as gorse is too). Its growth is fairly rapid and so its life cycle reasonably short. Its range in New Zealand is from about northern Waikato to southern Marlborough. Massey University reports that it can be a weed problem for farmers in eastern districts.

But everything on the plant has its place and a chapter in The Biology of Wetas, King Crickets and their Allies (CABI Books, 2001), edited by L H Field, notes weta insects have a special relationship with tauhinu, with the weta found on plants at night throughout the year, and feeding on the new shoots and flowers. (Click on the ‘weta’ link to read more about these amazing insects.)

Dates to note

If you’re intending to pop along to Laurie Jeyes’ rose-pruning demonstration and talk at Palmers Bethlehem this weekend, please note that the day is Sunday (not Saturday as I’ve had it listed till just now, sorry about that) and that you have two chances to see him in action – 1.30pm and 3pm. Laurie is very experienced and a good teacher.

I’ve also heard this week that there will be no Western Bay of Plenty Camellia Society show this year (usually in August) due to ill health. All going well, club members plan to be back next year.

Gael Blaymires has moved into Te Puke but Looking Glass Garden hasn’t yet sold and is still open to the public. Make a note now to visit during daffodil season as it may be the last chance to see the “host of golden daffodils”. The bulbs will start flowering from early August, Gael says, with peak blooming from mid-August to the end of the month. “Please wear sensible shoes,” she advises visitors.

Feeding the bees

Tree Crops Association branches are having sales – Waikato (July 4), Auckland (July 11) and Bay of Plenty (July 18). See the Events page for details.

Worried by a lack of bees in your garden? You should be for it is the bees and bumblebees that pollinate most of our fruit, nuts, vegetables and flowers but if New Zealand follows northern hemisphere trends these busy little workers are at risk – and so are our crops, whether domestic or commercial.

Bill and Elizabeth Rae, who have a kiwifruit orchard north of Katikati, have been following news stories and research on the threats to bees in Britain and the United States and are working to try and stop a decline in bee numbers here. They are members of the Bee Group within the Bay of Plenty Tree Crops Association – motto Bee Wise – and have compiled information and planting lists for gardeners.

Alnus jorullensis (Mexican alder) flowers in winter in the Western Bay of Plenty and is attractive to bees. Photo: Sandra Simpson

“There seems to be a lot of information for the commercial growers and not a lot for the home gardener, either on useful plants or the use of chemical sprays,” says Bill, a trained botanist and former teacher at Katikati College.

“Spraying on roadsides and under kiwifruit vines takes away flowering weeds, monocultural cropping takes away the diversity of pollen bees seem to need to stay healthy, and home gardeners aren’t necessarily planting to support bees, especially these so-called easy-care gardens with lots of stones.”

Research is showing that the decline in bee numbers may be down to reduced plant diversity – those with access to pollen from a range of plants had healthier immune systems, French scientists have found – while another European study in 2008 showed that bee numbers were declining in step with a reduction in wild flowers.

In 2010 the French government announced a project to sow nectar-rich flowers by roadsides, while the previous year the British government pledged ₤10 million to research ways to halt the decline in pollinators, including bees and butterflies.

“There’s a general concern around the world about the decline in bee numbers,” Bill says, “and being orchardists ourselves we’ve heard a lot about being careful with the bees that are brought in for pollination.”

If you have the space, banksia shrubs and trees are winter flowering and also attract nectar-eating birds. Photo: Sandra Simpson

In their own home orchard and vege garden Elizabeth sows mesclun salad plants and basil and encourages them to bolt to flower for the bees. “I’ve got lots of nepeta [catnip], borage, thyme and lavender that bees like, and corydalis flowers for a long time and is always covered in bees.”

She suggests an area planted in perennial wallflowers (erysimum) will help bee-food shortages from spring through to midwinter, and notes that so-called lawn weeds are of great value too – self-heal, clover and daisies. “I mow the lawn in areas now,” Bill says, “so there’s always something flowering in the grass for the bees.”

Good winter sources of nectar, according to Bill, are two weedy plants – gorse and mangrove, “perhaps worth considering when you say mangroves are useless”, he says. Other useful bee food includes conifers that, ironically, don’t need bees for pollination.

The Bee Group has made its information available to the Bay of Plenty Regional Council and it is posted on the Tree Crops Association website. See also the Trees for Bees website (includes a North Island and South Island planting guide).

USEFUL BEE PLANTS:
Winter: Puriri (flowers off and on all year), casimiroa, hazel trees, hardenbergia, rocket.
Spring: Puka, maples, apple trees, ajuga, rosemary.
Summer: Lancewood, tupelo, citrus trees, alyssum, mock orange.
Autumn: Houhere, viburnum, zinnia, echinacea, fuchsia.

A bee and a monarch butterfly are finding winter food in an aloe flower. Photo: Sandra Simpson

This article was first published in the Bay of Plenty Times and appears here with permission.