When and how do I divide my Gunnera?
“Divide large types before growth starts into single crowns in midspring.” (Source: American Horticultural Society Plant Propagation, ed. by A. Toogood, 1999, p. 198)
“Many gunneras are huge and so are impossible to dig up and divide in the conventional sense. For propagation, cut pieces from the edge of the clump. Pot up in a large pot and in a fibrous medium and keep moist.” (Source: The Complete Book of Plant Propagation, ed. by C. Heuser, 1997, p. 40)
The sources I looked at indicate that you should divide your Gunnera in April or May. Because of the size of the plant, it may be impractical to divide the rootball. You can use a spade or pitchfork to cut sections from the main clump, and then plant those divisions in pots, keeping them moist. Gunnera is a tough plant, and should take well to this kind of division, as long as there is adequate moisture.
Should you need to protect your Gunnera over the winter months, you can cut the leaves and use them like a tent to protect the crown of the plant during the coldest months.
I have grown Festuca glauca for many years. While they have an annoying propensity to seed themselves everywhere, I have never seen Festuca send off many little plantlets, as one of mine is currently doing. Of all the Festuca that I grew, this one got the least amount of sun, and was near other taller plants, and it was also probably exposed to the most humidity.
Is this really a sign of the Apocalypse, or just another result of a crappy summer?
We had lots of theories put forth by library staff and professional gardeners, but according to plant ecophysiology professor Soo-Hyung Kim, your plant is demonstrating vivipary (or in the case of plants like Festuca, which are in the family Poaceae, pseudovivipary). I found information about vivipary in an article by Thomas Elmqvist and Paul Alan Cox, published in Oikos, vol. 77, no. 1, pp. 3-9, October 1996.:
“Vivipary in flowering plants is defined as the precocious and continuous growth of the offspring when still attached to the maternal parent. Two main types, true vivipary (involving sexually produced offspring) and pseudovivipary (asexual offspring), may be identified. Vivipary has been described from slightly less than a hundred different species of flowering plants, of which we classify approximately 50% as having true vivipary, with the remaining species being pseudoviviparous.”
There is additional information in Flora of North America, vol. 24, p.392:
“Under adverse conditions, many species [of Festuca] may proliferate vegetatively, where leafy bulbils or shoots form in place of some or all spikelets. Some populations of Festuca are largely (or completely) sterile, reproducing almost entirely through such bulbils, a process termed pseudovivipary. Pseudoviviparous plants may be common or even abundant in certain areas and habitats.”
Some scientists (cited in Elmqvist and Cox article) suggest that pseudovivipary is an evolutionary response to a short growing season (as in arctic, alpine, or arid areas). Perhaps your plant is in its own microhabitat!
Why does my Heuchera lift out of the ground while growing? Should I replant it back down into the soil? If so, when and how do I do this?
I have observed this in my own garden and wondered why those heucheras keep heaving themselves out of the soil. According to Heucheras and Heucherellas by Dan Heims and Grahame Ware (Timber Press, 2005), most heucheras “require resetting or mounding every two years. A heuchera is in need of such a treatment when its rhizomes’ stems exceed three inches in length. […] Remove stem tips with a sharp knife or razor and plunge them into the ground or into potting soil to make more plants; lateral buds will emerge the following spring. Resetting a plant involves ‘popping’ the rootball out of the ground, digging a deeper hole in the same spot or elsewhere, and resetting the plant with 3 inches of soil mulch. It is important not to cover the crown tips, as this may cause rot or death. Some people think it is easier simply to mound 3 inches of mulch over the plant, but we prefer resetting–which is also a good opportunity for dividing the plant.[…] Early spring, when the ground thaws, is our preferred time for this operation. Without this treatment, many heucheras show less vigor, less flowers, and less foliage.”
Last year, I collected and propagated seed from my black mondo grass. I now have about a hundred healthy starts which are green in color, with leaves thicker than those of the parent black mondo plants. Is this just their immature color, or do they not come true from seed?
Most of the resources I consulted recommend propagating Ophiopogon planiscapus ‘Nigrescens’ by division of clumps in fall or late winter, but The Plantfinder’s Guide to Ornamental Grasses by Roger Grounds (Timber Press, 1998) says the following:
“The flowers are mauve, but the berries are black, and if sown will produce about one-third black seedlings, the rest being green.”
If all of your plants came up green, I would guess they will stay that color (in other words, they must have reverted to the species, Ophiopogon planiscapus, which has wider green leaves).
August is a good time to lift and divide your Bearded Iris, but don’t touch your Pacific Coast Native Iris until the rains return in fall. To learn more about the joys of growing this “Flower of the Rainbow” go to the American Iris Society’s website.
The King County Iris Society holds lectures and events throughout the year and publishes a monthly newsletter. Their annual rhizome sale is September 13 and 14 at Crossroads Mall 15600 NE 8th St, Bellevue. To join the society send $10.00 to KCIS Membership Chair, PO Box 95538, Seattle, WA 98145-2538. Online at www.kcis.org.
Could you provide some information on the propagation and division of Dierama (not sure if the species I have is D. pendulum or D. pulcherrimum. It has pink flowers and is also known as Angel’s Fishing Rod)? The clump has gotten large and I’d like to see if I can divide it now in fall.
The Royal Horticultural Society has an advice page on how to divide and propagate Dierama.
Excerpt:
Named cultivars can be propagated by division in spring or immediately after flowering; but this should only be undertaken occasionally as plants are slow to re-establish. Plants grow from corms that build up year by year into chains, similar to Crocosmia.
- Lift plants and separate corms, reducing the foliage by half with secateurs.
- Take care not to damage the brittle, fleshy roots.
- Divisions take one to two years to flower freely again.
For an answer from local experts, I consulted Perennials: The Gardener’s Reference by Carter, Becker, and Lilly (Timber Press, 2007). The authors say that “it’s best not to transplant, divide, or groom in the fall.” Instead, if you must divide, do so in April or May and include several corms in each clump. You can also sow ripe seed at that time. Seed may be harvested by shaking the stems.
A list of the best books, articles and websites on plant propagation.
Take root cuttings in autumn, once rain has arrived, to make new plants of many popular perennials like oriental poppies, verbascum, garden phlox and black-eyed susans. The September/October 2004 issue of Horticulture Magazine gives clear instruction on this easy propagation technique, and suggests many other suitable plants. In a nutshell:
- lift the plant to be propagated with a garden fork
- shake off soil to expose the roots
cut out a few roots that are about the thickness of a pencil, noting the “top” of the root (closest to the plant)
- cut the root into 2 inch pieces
- insert the pieces into a small container of potting soil, with the top end just under the surface
- keep the container moist, not wet, and inside in bright light until new growth appears
- transplant into individual pots when growth is a couple of inches tall
Early fall is that magic season in the garden when a good soaking rain and warm soil trigger a flush of new growth in perennials and some shrubs before cold temperatures slows everything down. This explains why now is an ideal time to transplant, divide and otherwise shuffle around your plants. For an illustrated essay on techniques and timing of dividing perennials go to: Clemson University Extension.