We talk about it more and more, it has been the star of simple and natural gardens for some time, but what is Alcalthaea?
Why such a weird name for a lavater?
This plant of the Malvaceae family, of its full name (x) Alcalthaea suffrutescens, is in fact the result of an inter-genus cross between the tree marshmallow (Althea) and the hollyhock (Alcea) which gives Althaea x Alcea, baptized (x) Alcalthaea.
When we look at the varieties, we can clearly distinguish the foliage, the shrubby and branched shape of Althea and the shimmering colors of the hollyhock without having the faults of the latter, namely leaves stained with rust. For the moment only 3 varieties are offered ‘Freedom’ with pale pink flowers shaded with light garnet, ‘Parkrondell’ with pink-mauve flowers with gray reflections and ‘Parkallee’, by far my favorite at the moment, with a rather indefinable color, a blend of light apricot, buff and creamy yellow with a crumpled bouquet in the center of stamens and petals.
To plant where and for what use?
Like all Malvaceae, Alcalthaea love the sun and light soils, they adapt very well to limestone and poor soils and tolerate drought fairly well … They are resistant to many things: wind, frost, a relative Brief summer drought, they grow everywhere, except in the shade, in heavy and humid soil.
They are very easy to use plants, they are less structuring than a hollyhock and take much less space than a lavatera, suddenly they can be used in a romantic garden with lychnis coronaria or yunnanensis, bellflowers’ Kent Bell ‘, umbelliferae or quite simply roses, or like me, in a garden of grasses, in the natural style. you can use it with grasses, a real favorite for Alcalthaea associated quite simply with Allium christophii or ‘Globemaster’ and pennisetum alopecuroides which can just as easily be replaced by Stipa tenuissima or Stipa barbata en masse. It’s very simple, but it works well and for a long time.
If you have heavy, clayey soil, add a good third of sand and gravel to the planting, and install the stump on a mound or embankment. Last advice, after 2-3 years, the Alcalthaea have the annoying tendency to have an erect habit, pinch them during May-June, they will be stockier, more floriferous and in the south, will suffer less from the summer drought.