on dividing Gunneras

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.

edibility of Mahonia species

Are the fruits of Mahonia x media ‘Charity’ edible, similar to Mahonia x media?

First, an aside: Mahonia has been ‘moved’ to Berberis, so that now Mahonia x media is named Berberis x hortensis, and Mahonia aquifolium is now Berberis aquifolium. Since the resources I will be quoting use the former names, I will leave them as they are.

Here’s what British author Alys Fowler says in her book, The Thrifty Forager (Kyle Books, 2011):

“All Mahonia species are edible, long-used for jams and juices in their native homes […] Sometimes you’ll find Mahonia nervosa, the Oregon grape, with the roundest grape-like berries. It looks very like Mahonia aquifolium but usually fruits later, around early autumn. […] Even when fully ripe, the acidic berries [of all Mahonia species] are too bitter to eat raw–they should be cooked into pies, jellies and jams. The flowers are edible, but bitter. The fruit needs to be picked and processed into jam or jelly very quickly, and it stains everything. It’s very low in pectin, so either add crab apples or add liquid pectin, following the usual jam making rules. You can also make an Oregon grape cordial which tastes a bit like blackcurrant cordial. Because of the low sugar content, it will need to be frozen if you want to store it–it’s a very sharp cordial, I use 350-400g (just under 1 lb) if granulated sugar to 600 ml (1 pint) of fruit. If that’s still too sharp, try mixing it with concentrated apple juice to sweeten it.”

Plants for a Future Database has pages for several Mahonia and Berberis species, including Mahonia x media, and its fruit is listed as edible.

On quinoa

What is quinoa, botanically? Is it a grain, or something else?

The botanical name for Quinoa is Chenopodium quinoa. According to information from the Alternative Crops Manual produced by University of Wisconsin Extension, it is an annual plant in the goosefoot or Amaranthaceae family, which also includes the familiar weed, lambs’ quarters or Chenopodium album. This article states that “Quinoa is sometimes referred to as a ‘pseudocereal’ because it is a broadleaf non-legume that is grown for grain unlike most cereal grains which are grassy plants. It is similar in this respect to the pseudocereals buckwheat and amaranth.” Edible: An illustrated guide to the world’s food plants (National Geographic, 2008) states that true cereals are members of the Poaceae or grass family, but quinoa more closely resembles spinach. It was first used as a food plant around 5000 B.C.E. near Lake Titicaca in the Andes, where it is native. Its common name in that region is “the mother grain.”

Incidentally, the Food and Agriculture Organization of the United Nations declared 2013 the International Year of Quinoa, “recognizing the Andean indigenous peoples, who have maintained, controlled, protected and preserved quinoa as food for present and future generations thanks to their traditional knowledge and practices of living well in harmony with mother earth and nature.”

Ammonium sulfate and organic guidelines

Is ammonium sulfate considered an organic fertilizer? I’d like to use some on my blueberries, but suspect it is not organic.

According to Fertilizers and Soil Amendments by Roy Hunter Follett (and others), ammonium sulfate is one of the oldest chemical fertilizers, and is “a frequent by-product of the steel industry, particularly the coking of coal.” That doesn’t sound like it meets organic guidelines. It is also tricky to use because it can cause phosphorus and aluminum to build up in the soil. The Organic Materials Review Institute lists it as a prohibited (for certified organic growers) synthetic crop fertilizer and soil amendment. You might do better using a slow-release certified organic fertilizer labeled for acid-loving plants. Cornell University Extension’s publication, Production Guide for Organic Blueberries” mentions fish, soy, and alfalfa meal as organic-acceptable amendments.

Pine needles as mulch

Are pine needles good for mulch in the garden and for fruit trees?

Pine needles are most often used with plants that prefer acid soil, but according to Mulch It! by Stu Campbell (Storey, 2001), they can be used elsewhere, too, at a depth of one to one and a half inches. It is considered a myth (see information from Washington State University horticulture professor Linda Chalker-Scott in Organic Gardening, February 2007, p.8) that they will acidify your soil. They are good for insulation, weed control, and moisture retention, and excellent for water penetration. However, they decompose very slowly and are not liked by earthworms. You can shred the needles a bit before applying them as mulch, and that will speed their decomposition.

Toxicity of Eucalyptus trees

I have a young Eucalyptus pulverulenta tree. I’m concerned that it might be emitting toxic chemicals into the surrounding soil that will harm other plants. Is this indeed a cause for concern?

My instinct is that your Eucalpytus tree will probably not be toxic to most other plants. Eucalyptus is often seen growing in the midst of garden beds here in Seattle, to no ill effect. I have a tree growing in a perennial bed, and have noticed no problems. However, the leaves do contain essential oils (phenolics and terpenoids). This does make the tree more flammable, if that is a concern. Eucalyptus leaf litter (to a greater degree than exudates from the tree’s roots) can inhibit specific food crops, like wheat. This is what is meant in this University of Florida Extension article (now archived), which refers to “selective activity of tree allelochemicals on crops and other plants.”

To show how selective this chemical property can be, see the following documentation of a University of California, Davis experiment using composted Eucalyptus as mulch.

Excerpt:
“Mulch products made from Eucalyptus are an asset to maintenance of fine landscapes. Composted Eucalyptus makes an excellent seed cover and will aid in germination and establishment of seedlings such as California Poppy. Fresh Eucalyptus is an excellent mulch for woody landscape plant materials and palms; the main effects of its use are weed control and water conservation.”

Unless you are growing your tree in the middle of a field of wheat or among other grassy plants, your landscape is probably in no danger of inhibited growth from the Eucalyptus.

You may find the following veterinary perspective (from Cornell University) on the toxicity of Eucalyptus of peripheral interest.

Liquidambar and its Latin roots

How on earth did Liquidambar enter the otherwise Latin list of genera? I have asked a lot of gardening experts, and no one else seems bothered by this. Can you assuage my anguish?

There are quite a few botanical (scientific) names that are not Latin in origin–many are Greek, or modeled after the name of the plant explorer who ‘discovered’ them, or the plant’s geographical origins, to name a few possibilities.

Liquidambar actually does have Latin roots. According to Geoffrey Grigson’s A Dictionary of English Plant Names (Allen Lane, 1974), Liquidambar styraciflua, a native of North America and Mexico, was introduced in 1683. The name refers to the tree’s fragrant gum or resin:

liquidambar (liquidus, ‘liquid,’ + medieval Latin ambra, ‘amber’)

A Spanish physician, Francisco Hernandez, coined the name in the 16th century. “The gum was sold in apothecaries’ shops as Balsamum liquidambrae.” The species name, styraciflua, is derived from a Latin phrase meaning ‘storax fluid.’ From the following article in the Bulletin of Hispanic Studies, Volume 86, I discovered more information about storax:

“According to Dioscorides:

storax is the sap of a tree which resembles the quince tree. The best is yellow, fatty and resinous; it has whitish lumps, its scent lasts for a very long time and when softened, it releases some honey-like moisture.“

Propagating asparagus plants

I planted young asparagus plants a couple of springs ago. This past fall, one of the plants produced fruits (small red balls like I’ve seen on Asparagus sprengeri.) I looked in my Hartman and Kester, but it did not mention means of using asparagus seeds to make more plants. Can this be done? If I left them on the plant outside all winter, are they still viable?

According to Franklin Herm Fitz in A Gardener’s Guide to Propagating Food Plants, it is possible to grow asparagus from seed, but possibly not if the seeds have been out in freezing weather:

“Collect the red berries from two-year-old or older female plants, harvesting before the first frost. Crush the berries and separate the seeds by hand (the seeds are large, shiny, and black) or by immersing them in water. The pulp will float as the seeds sink. Dry the seeds for 2 to 3 weeks. In the spring grow the new plants in deep, loose soil. After one season transplant them to a permanent bed (…) in early spring before growth resumes or in the fall after growth has ceased.”

Alternatively, as you probably know, asparagus roots may be divided and replanted, with the knowledge that each smaller root will take a year to become established so that it can produce a good crop.

On the lifespan of arborvitae trees

What is the typical life of an arborvitae tree?

Arborvitae is the common name of Thuja, usually Thuja occidentalis. As
with human beings, lifespan can only be an estimate, due to various
circumstances which affect health and longevity. Urban growing conditions
differ from those experienced by plants growing in the wild, for example.
An article in The International Journal of Plant Sciences, Vol. 153, No. 1 (March 1992) by P. E. Kelly, et al. suggests that T. occidentalis growing
on cliffs of the Niagara Escarpment in Ontario, Canada could be over 1,000 years old.

The record for this tree in the Urban Forest Ecosystems Institute
database, SelecTree, indicates that its lifespan ranges from 40 to 150
years. Columnar arborvitae, Thuja occidentalis ‘fastigiata,’ is listed as having
a lifespan of 50 to 150 years.

The Lady Bird Johnson Wildflower Center provides more information on Thuja occidentalis, too. Here is an excerpt:

“In a crowded environment, this tree is slender and not well-branched. In
the open, it improves in form and density. The evergreen can be single-
or multi-trunked and columnar or conical in shape. Eastern arborvitae can
grow 40-60 ft. tall, but under cultivation will probably be no taller
than 30 ft. Branches end in flat, spreading, horizontal sprays of
fragrant, dark-green foliage which turns yellow-green or slight brown in
winter. Resinous and aromatic evergreen tree with angled, buttressed,
often branched trunk and a narrow, conical crown of short, spreading
branches.

Probably the first North American tree introduced into Europe, it was
discovered by French explorers and grown in Paris about 1536. The year
before, tea prepared from the foliage and bark, now known to be high in
vitamin C, saved the crew of Jacques Cartier from scurvy. It was named
arborvitae , Latin for tree-of-life, in 1558. The trees grow slowly and
reach an age of 400 years or more.”

An article from the May 2002 issue of the Journal of
Arboriculture lists Thuja occidentalis as a long-lived tree with a medium
growth rate. They define “long” as over 200 years. However, most
arborvitae one sees in urban landscapes would be unlikely to survive that
long, due to many variables (poor planting methods, overcrowding,
pollution, exposure to lawn chemicals, etc.).

Moving mature trees

I need advice on moving a Japanese Maple tree. The tree
is 10 feet tall, and has begun to grow unevenly
because it was planted too close to a very large wisteria in
front of our house. Ideally, we would only move it 8-10 feet,
as there is a wide open space with lots of sunlight just east of its
current home. I don’t know how deep the Japanese Maple typically roots,
or how difficult this may be, but any information you
could provide would be very much appreciated.

According to the book Japanese Maples by J. D. Vertrees (Timber Press,
1987), Japanese maples do not have deep, tap-root structures, but are
mainly a fibrous root network which stays in the upper level of the soil.
As they mature, however, there will be roots going deeper, so if you are
planning to move the tree, you will want to be sure to get as much of the
root ball as possible. If the tree is not too old, it should be easier.
Make sure to water the tree well and prepare the new site before you
begin digging carefully.

The Royal Horticultural Society has general information on moving
mature trees and shrubs which may be of use to you, keeping in mind that
fall is a good time for you to move a tree here in the Northwest.

You can also contact a certified arborist for advice. For a referral,
contact Plant Amnesty.
You can also go directly to the local chapter of ISA, the International
Society of Arboriculture.