Friday, August 29, 2014

The Yellow, Yellow, Days of August

Now, before the muttering starts in the back row, let me assure you that I am quite well aware that some gardeners dislike yellow. Some even go so far as to avoid having any yellow flowers in their gardens. They moan about the yellow centres of certain blooms, and grumble about yellow-leaved hostas. Their gardens, in August, are symphonies of pinks and mauves and blues.

I am not one of them.

I love yellow and cannot imagine August without it. Since many of the August yellows are daisies, you can say I like yellow daisies.

Of which there are many, and many that get called Black-eyed Susan. There is a lot of confusion among gardeners about these. I hear even knowledgeable gardeners call things Black-eyed Susan that barely even resemble the real Susan.

One is Rudbeckia triloba. It is easily recognized - the only Rudbeckia with leaves divided into three substantial lobes.

By the way, I hear people saying 'Rude-eh-beck-ee-a'. Do not make this mistake! The genus is named after Olof Rudbeck the Younger. He was a friend of Linnaeus, who named the genus to honor both him and his father. So, 'Rud-beck-ee-a', please.

R. triloba is tall and gangly, with relatively small flowers held above the rough foliage. It isn't impressive in the garden, but can anchor an empty corner. A well-grown plant can be covered with flowers, but even then it suffers from a degree of stodginess.

The best, maybe only, way to propagate this plant is to grow it from seed. It has a taproot so doesn't move or divide easily.

Much more attractive is R. laciniata.The form we usually see in the garden is the variety 'Herbstsonne' and yes, that is spelled correctly. If you need to say the name out loud, try to get into a German mood first and divide the word into three almost-syllables, as in 'Herbst-sonn-eh'.

It too is tall. In fact, there is some thought that it may be a hybrid with R. triloba, but nobody is really sure. It comes true from seed, so perhaps it is not a hybrid. The plants are mounds up to about 3', and the flowers stand well above that.

The petals droop gracefully and can be surprisingly large. A flower would be 6" across if the petals stood straight out. Each bloom lasts quite a while, and many can be open at once. It is a good cut flower, too.

Unfortunately, the flowering stems do tend to get blown over by the wind or bent down by the rain. If you want them to stand up you'll have to do some work with stakes and string.

Probably one of the most popular and best-selling perennials of all time is Rudbeckia fulgida variety Sullivantii, cultivar name 'Goldsturm'. This plant is the nurseryman's dream. It is rock-solid hardy, totally perennial, looks good in a pot, always blooms and for a long time, always the same size, grows in sun or semi-shade, grows in dry or moist soil, is easy to propagate, so what's not to like?

Here is one separate plant to show the form and shape. It has substantial basal leaves and many stems. The flowers are totally uniform and held well up in the air. The colour is a strong chrome yellow, tending a bit towards orange.

In evening light, the flowers are much more orange, almost luminescent. It looks wonderful among tall grasses.

This is R. fulgida, common name 'Orange Coneflower'.

'Goldsturm' spreads by producing multiple crowns, and by seeding itself around. If I understand it correctly, we are not supposed to call the seed-grown offspring of named cultivars by the parent's cultivar name, so let's just say that once you have a plant of R. f. s. 'Goldsturm', you will soon have many not-Goldsturms. They will look and act exactly like the parent.

The thing not to like about this is that it does get a bit boring.

Much more interesting, to my mind, is the real Black-eyed Susan, Rudbeckia hirta. Here is a picture comparing the stems of R. hirta and R. fulgida. The former has lots of rather prickly hairs, the latter only a few and they are much softer.

The other big difference is that R. hirta is a biennial. It puts up a cluster of basal leaves in the fall, then produces its flowers the next summer. It is totally hardy and very easy to grow. Just leave the small plants where you like them and leave them alone. You can transplant them when they are still small, but they don't like it.

There are quite a few cultivars for which you can buy seed. One of my favourites is (was, really), Cherokee Sunset. It was (is) fully double and a cheeky yellow-orange. It's offspring will vary wildly, so if you want Cherokee again, you'll have to buy new seeds. I grew some from seed once and since then I've enjoyed the many variations in the flowers of R. hirta not-Cherokee Sunset.

The lower picture on the right, by the way, is very similar to the one called 'Toto', but of course we're not going to call it that.

And now, drum roll please, the real Black-eyed Susan, R. hirta itself, plain and unimproved and growing as it grows best, in the wild with Goldenrods and grasses.

1 comment:

  1. Yellow in August is, of course, perfect as it mirrors the yellowing of the sunlight at this time of year. I bought a R. laciniata last year and was thrilled with its long lasting blooms. This spring a rabbit (aargh!) decimated it and only one scraggly leaf is left. I am really hoping that it will come through next year.