Tag Archives: Abbie Jury

Plant Collector: Rhododendron Rubicon

Rhododendron Rubicon - in our opinion, the best big red in the country.

Rhododendron Rubicon – in our opinion, the best big red in the country.

In the world of red rhododendrons, Rubicon stands clear of the rest – at least in my opinion. It is the purest of reds without that common tendency to develop pink tones as it ages, has lovely foliage and a very tidy, rounded habit. It is pretty much perfect in that big full truss class. I should perhaps have qualified my first sentence by saying in the New Zealand world of red rhododendrons because I don’t know how successful it has been overseas but it sure beats the imported varieties we grow. It was bred by the late Ron Gordon from Taihape and first became available in the late 1980s. It is a cross between Kilimanjaro and Noyo Chief and it is superior to both its parents though it was the latter which contributed the good dark, heavily veined foliage that is a feature of Rubicon.

The one downside for us is that Rubicon can get attacked by thrips – those nasty, leaf sucking critters which turn rhododendron leaves silver. Because our plant is in such a prominent position, it is one of the few Mark will spray here. He uses an insecticide but other people report good results using Neem oil to beat thrips.

Rubicon is widely available on the market in this country and is an essential in any collection.

First published in the Waikato Times and reprinted here with their permission.

Garden lore

It is obvious that close planting [of shrubs] gives a furnished look to a border almost immediately, equally obvious that it is wasteful and expensive.

The Well-Tempered Garden by Christopher Lloyd (1973).

Dead heading rhododendrons

The usual advice is to dead head all rhododendrons. In fact, while they all look a great deal better for dead heading, it is really only necessary to do the ones that set seed. You will be able to tell by looking, if you didn’t do them last year, because they will have spent pods similar (but almost certainly smaller) to the ones shown in the photo. Some rhododendrons can set so much seed that they weaken themselves and eventually die. My neighbour swears by coating his fingers in olive oil before he goes out to dead head. It stops the gunky residue from making your hands sticky.

For the love of wisteria

Blue Sapphire - a classic blue sinenis wisteria

Blue Sapphire – a classic blue sinenis wisteria

I am feeling the love for wisterias. This love does not last 52 weeks of the year, but when they are in flower, you would have to be lacking in all romance not to admire them. This week it is Blue Sapphire that is looking its very best. White Silk and Amethyst are just opening, to be followed by Snow Showers and Pink Ice. Even the very names are romantic and evocative.

If you have your wisteria beautifully trained and tied in across your verandah (best with an equally romantic looking old villa or cottage) where its long racemes of fragrant flowers festoon down, so much the better. All you need is the rocking chair with calico cushions to complete the picture. I don’t go there, because I know that in the 49 weeks of the year when it is not flowering, that plant is going to take on triffid-like characteristics and try to split the spouting and drive a wedge between the roof and the ceiling. The oh-so-lovely blue wisteria on the side of our house was eradicated years ago. I was too much of a novice to understand why Mark’s father took it out when it looked so beautiful in flower, but now I understand just how quickly a wayward tendril can leap into a gap in the roof tiles, thicken, harden and bingo, you have a broken tile before you’ve even noticed it got away on you.

One growing season is all it takes. Believe me. I have had the lovely Snow Showers split the plastic spouting immediately outside my office window and I prune thoroughly every year. By autumn, one stem had driven such a wedge between the spouting and the building that something had to give.

Snow Showers - a floribunda selection on our bridge

Snow Showers – a floribunda selection on our bridge

Growing wisteria takes a bit of work. You need to prune them and to train them and picking a suitable location is important. Currently we grow a couple over a wooden bridge (and they have made an attempt to split the bridge timbers), three up strings on a brick wall where they can do no harm beyond leaping into nearby trees if not supervised closely and the aforementioned one up a wooden wall out my office window. I have two waiting to be planted out and they will be going on freestanding metal frames which will support a canopy over time. A bit of forethought can save a lot of trouble later. Wisterias are not something you can plant and leave. I was once told that the largest plant in the world is a wisteria which has layered and leapt its way along 5km somewhere in China. I have no idea if it deserves the title of the largest plant, but I have little doubt that such a one exists.

There are two main groups of wisterias, the Chinese ones (“sinensis” which just means from China) and the Japanese ones (floribunda). The Chinese ones usually have finer leaves and they flower on bare wood before the spring foliage appears. As a relatively random piece of information, the Chinese ones twine anti clockwise whereas the Japanese ones twine clockwise.

Wisteria White Silk

Wisteria White Silk

The floribunda wisterias flower as the new foliage appears but to compensate, they tend to have much longer racemes of flowers. Some can be 50cm or more and, as the plant gains maturity, the flowers just get better. White Silk (or Shiro Kapitan) is an exception with its short, fat racemes but it makes up in flower size and heavy fragrance what it lacks in festooning capacity. There are also North American species and I have yet to discover whether they twine clockwise or anti clockwise. The ones most commonly available on the market here originate from China and Japan. The flowers resemble pea and bean flowers and indeed wisterias are members of the legume family.

The trunks of these vines are borer fodder supreme. If you look at an old wisteria, you are almost certain to find extensive borer damage. They battle on remarkably well for quite a long time, but left untreated, sooner or later sections will die and snap out. It pays not to put all your trust in one central leader or even a central plait of three leaders. Sooner or later, the borer are likely to take them out so you want to be training the occasional replacement through as well.

Whenever you spot a borer hole or borer sawdust, treat it. Either cut it out or pump the hole full of insecticide (fly spray seems to work) or light oil such as a cooking oil. I favour CRC because the spray cans come with those handy little tubes for poking down the hole.

If you are willing to put the work into managing your wisteria, they will reward you in a most gratifying manner.

Wisteria Amethyst

Wisteria Amethyst

Help! My wisteria won’t flower.
1) Check for borer infestation and make sure the plant is still alive.
2) The sparrows may have disbudded it. Sometimes they develop a taste for the buds but you should see freshly damaged debris lying below.
3) The plant has been pruned incorrectly in winter. If you cut it back to a stump every year, you are cutting off all the flowering spurs. Sort out the main stems and then prune back all the side canes to three or four buds out from the main framework. That is where the flowers develop from.
4) You have bought a seedling instead of a named variety. Replace it.
5) You have a grafted plant and the root stock has taken over. We much prefer cutting grown wisteria so this problem does not arise. If you can identify what is root stock, remove it to allow the grafted variety to grow without competition. These days, most plants are cutting grown.

First published in the Waikato Times and reprinted here with their permission.

Plant Collector: Rhodohypoxis

Pretty little rhodohypoxis - Ruth (white), Susan (pink), Albrighton (dark)

Pretty little rhodohypoxis – Ruth (white), Susan (pink), Albrighton (dark)

As the peak time for spring bulbs passes over, the South African rhodohypoxis come into their own. These are cracker little plants, forming a colourful carpet in well drained, sunny conditions. They are also great in wide, shallow bowls or underplanting shrubs in containers, as illustrated. Their fresh growth is triggered by autumn rains and they have a long flowering season from mid spring into early summer, as long as they don’t dry out. The foliage is short and grassy and hangs around unobtrusively until autumn when the plant goes dormant for a brief time.

There are a mass of different named rhodohypoxis, though most are just selections of R. baurii. Essentially they come in sugar pink, deep pink to red, white, bicoloured variations and occasional double forms. They are really easy to grow and multiply up most satisfyingly, with one proviso. The rhizomes are tiny and dark brown – sometimes not unlike the clawed ranunculus and other times just small, brown lumps. This means they are alarming anonymous when dormant and I am sure that is when most people forget where they are and either flay them round when weeding or plant something on top of them. If in doubt, plant them in a pot and sink the whole pot in the garden while you build up numbers.

With a rhodohypoxis expert staying here this week, we had a discussion on whether these bulbs are technically tubers, corms or rhizomes. The internet uses all terms interchangeably. The decision came down fair and square on rhizome status.

First published in the Waikato Times and reprinted here with their permission.

Garden lore

It surprised him to discover that gardening, for all its air of prelapsarian serenity, is furiously competitive, frequently indulged in by the envious, the deceitful, the quietly criminal.

The Pedant in the Kitchen by Julian Barnes (2003).

Onehunga weed or prickle weed in the lawn.

Onehunga Weed

Onehunga Weed

The greatest curse of the lawn is the prickly Onehunga weed. If you know you had it last year – prickles in the feet- now is the time to act. It will take several years to eradicate entirely, but it will get worse if you leave it. You want to break the cycle and stop it from setting seed in early summer. These weeds are annuals – usually they germinate in autumn, romp away in spring (right now, in fact), flower, set seed and prickles and die as lawns dry out over summer. If you only have a little, hand weed it. There are specific sprays developed for Onehunga weed (ask at your local garden centre). We prefer to let the grass grow considerably longer than usual and then follow up in two to three weeks time by cutting it very short – scalping it in fact. The growth stretches the Onehunga weed up and it does not survive being cut very short. Timing is of the essence – if you leave it too late, the prickles and seeds will be developing. Onehunga weed does best in poor conditions. It is not so good at competing in a lush, healthy lawn.