how poisonous are poinsettias?

Just how poisonous are poinsettias? My mother lives in a nursing home, and the director just confiscated nearly 200 potted plants that were donated to residents for the holidays. I think he overreacted. Do you agree?

I agree with you. It is a fact that poinsettias (Euphorbia pulcherrima) are in the Euphorbiaceae family, and the sap of plants in this family is irritating to the skin and eyes. However, it seems highly unlikely that people would be exposed to the sap of these plants, and it would take eating large quantities of leaves to become seriously ill. It’s not a good idea to eat the leaves of most indoor plants, in any case.

There is information about the degree to which poinsettias are poisonous on the following sites:

It’s possible the director of the nursing home was alarmed by a recent news story about a local woman who went to the emergency room after weeding in her garden and getting Euphorbia sap in her eye. There is a big difference between stationary houseplants which one mainly looks at without touching, and the aggressive and weedy Euphorbia species one pulls from the garden (only with gloves and goggles)!

on planting Darwin tulips

Will my Darwin hybrid tulips come back every year?

In his book Ask Ciscoe (Sasquatch Books, 2007), local garden expert Ciscoe Morris suggests planting Darwin and Empress hybrid tulips 12 inches deep (rather than the often recommended 6 inches) so that the bulbs will be less likely to divide and the squirrels less likely to dig them up.

Ann Lovejoy says much the same thing…plant tulips 10 inches deep, in a sunny spot, and in well-drained soil, and some are likely to return for several years. (See Seasonal Bulbs, 1995, p.16)

on glossy-leaved fringe trees

Which varieties of fringe tree have glossy leaves? I am especially interested in a comparison between C. virginicus and C. retusus.

More than one variety of fringe tree (Chionanthus) is described as having lustrous leaves. According to Michael Dirr’s Dirr’s Hardy Trees and Shrubs (Timber Press, 1997), Chionanthus retusus has “3- to 8-inch long, lustrous dark green leaves,” while C. virginicus has “3- to 8-inch long leaves [which] vary from medium to dark green, with various degrees of gloss.”

If you wish to see images, you can search Google images with the different species names. Oregon State University’s online guide to Landscape Plants has good detailed images and descriptions of these two species of Chionanthus.

lists for invasive and noxious weeds

Can you provide me with an extensive list of resources for checking whether a plant is invasive or a noxious weed?

Here is a list of helpful resources:

Washington State Noxious Weed List from the US Department of Agriculture

State noxious weed list and schedule of monetary penalties from the Washington State Legislature

Class A, Class B, and Class C

Washington Department of Ecology (aquatic plants)

Washington Invasive Species Coalition and their GardenWise handbook

King County Noxious Weed Lists

National Invasive Species Lists

Plant Conservation Alliance Alien Plant Invaders list

Invasives in British Columbia

The lists which are national in scope are useful too, as some plants not
yet officially listed as invasive here may still be plants to watch out
for.

There are a great many books on this subject. A recent one, co-authored
by a faculty member here, is Invasive Species in the Pacific Northwest edited by P.D. Boersma, S.H. Reichard, and A.N. Van Buren; Rebecca L. Gamboa, photo editor.
University of Washington Press, c2006.

fast-growing shrubs for privacy

I will be having a very overgrown, rarely pruned laurel removed from my back garden. It has been, if a monstrosity, an effective visual screen. The bare area that it leaves is appproximately 40′ in length, is atop a rockery, approximately 3′ high, and will look up into the neighbor’s back hillside, while they peer down at us in dismay. Can you suggest one or several fast growing, shrubby plants or suitable trees that will act as an attractive visual screen? I do not want bamboo.

Here are a few ideas:

Morella californica

Thuja occidentalis ‘Smaragd’

Osmanthus delavayi is also a good choice, but it doesn’t get quite tall
enough–my own hedge, which is pruned at least twice a year, is about 8
feet tall, so if I really let it go, maybe it would be 10-12 feet.

Juniperus scopulorum ‘Wichita Blue’

Juniperus virginiana ‘Manhattan Blue’

Viburnum tinus

Ceanothus would also be striking, with blue flowers, but you’d need to
find the tallest possible species, and they tend to be short lived.

You could plant a mixed hedgerow, which would allow you to include some of the flowering plants you prefer. King Conservation District has more information on hedgerows.

usage of sawdust as mulch

We recently had a large blue spruce tree cut down and had the stump ground. Would the resulting sawdust be a good mulch for roses?

Also, what is your opinion of using a pre-emergent herbicide for weed
control in our rose bed?

Sawdust has high carbon content and may rob soil of nitrogen and moisture. It is also recommended for acid-loving plants and may be problematic for roses. There may also be compaction problems with sawdust, so it may need to be combined with other mulching materials to improve water penetration. Sawdust also decomposes slowly and compacts (Source: Mulch It! by Stu Campbell, Storey Communications Inc., 2001).

You may also be interested in two articles by Linda Chalker-Scott. In Wood chip mulch: Landscape boon or bane, she discusses the pros and cons of wood chip mulch. She also comments on sawdust in an article called The Myth of Pretty Mulch.

If you had spruce chips, they would be fine for mulching roses. Avoid
letting mulch touch the main stem; the goal is to pile it on the root
system away from the stem. You can remove it in the spring, or at least
be sure that it’s not too deep. While mulch protects from cold in the
winter and drought in the summer, if it’s too deep, water cannot get to
the root zone of the plant.

I would recommend that you avoid chemicals, as I find that you have to pay more attention when you use them than if you just wander through the garden now and then and pull all the weeds you see.

Pre-emergent weed controls never provide complete weed control. The most important thing to do is weed the area first, as pre-emergents only control weeds that have NOT sprouted. And if you have lots of seeds in the soil, don’t expect weed killer to eliminate them all. If water is required, beware of too much water (i.e., rain) that can wash away the herbicide.

Rather than use a chemical, I would weed the area now and then apply mulch. In addition to protecting the roots and soil, the mulch will suppress weeds, possibly until spring. You will have to watch for weeds that do sprout and be sure that you don’t let them go to seed. Otherwise, you will set yourself up for lots of future weeding. Chemicals don’t really help in situations like that, as you have to time their application perfectly. Hand weeding and mulching–well timed–can work better than any herbicide.

best time to fertilize rhodies, azaleas, and roses

Is it okay to fertilize my rhodies, azaleas, and roses in September? I missed
doing it in August.

Generally speaking, it is best not to fertilize your shrubs after mid-summer. The tender new growth that results is susceptible to frost, disease, and insects just at the time of year when the plant is beginning to shut
down. This is also true of roses, which are even more tender and susceptible than rhododendrons and azaleas.

An article by Terri Richmond (British Columbia) on the American Rhododendron Society website, entitled Fertilizing Rhododendrons the Organic Way supports the practice of fertilizing in spring. (Keep in mind that azaleas are in the same genus as rhododendrons.)

Oregon State University Extension suggests that budbreak in spring is a good time to fertilize roses, just as new growth is beginning. Stop fertilizing in late summer. Oregon State University also weighs in on fertilizing rhododendrons (if needed, in spring shortly after flowering, and preferably with organic fertilizer).

lack of flowers in star jasmine vines

I bought an established, white star jasmine perennial vine one year ago. I was told I could plant it in an extremely large pot and expect to enjoy blooms for about 3 years, but it has not bloomed, nor does it have any buds. It has no pests or blight of any kind. It gets full sun in the morning and partial during the day, and full again in late afternoon. It has always had sufficient water. What’s wrong? When do they normally bloom? Was I given inaccurate information?

I am assuming the star jasmine is Trachelospermum jasminoides, as shown in this image from Missouri Botanical Garden.

Failure to flower can be due to a number of causes, as described in this link from University of Vermont Extension.

My top guesses for what may be causing the lack of flowers would be exposure to
severe cold in the winter, or over-fertilizing with a nitrogen-heavy fertilizer.
The light exposure you describe sounds fine for this plant. In the Pacific
Northwest, it flowers mainly from spring to early summer. This link to
a Seattle garden writer’s site has cultural information appropriate for this
region (I don’t know where you are writing from).

growing moss indoors

Can you provide me with information on growing moss indoors? Also, do you know if Tolmiea is known for being fragrant?

Here is an article(now archived), “Indoor Gardening with Moss” by Robert Paul Hudson, from the Eugene Daily News. The author provides directions on maintaining a small terrarium with moss.

The web site Bizarre Stuff is another resource.
Excerpt:

Mosses can be grown in terrariums fairly easily. Collect moss from an
area where it is okay to do so and transport in plastic sandwich bags.
Sprinkle with water and seal the bag if you won’t be setting up the
terrarium right away. Use a large, clean glass jar with a tight fitting
lid. Lay it on its side in a shallow box or on a stand so that it will
not roll. Place sand and pebbles about 1/2 inch thick in the bottom of the
jar. On top of this place some of the soil from the same place where the
moss will be collected, or mix a soil of charcoal, light gravel, leaf
mold and garden soil. The soil should be level with the opening of the
jar. A little sulfur scattered on the soil will help to prevent mold from
growing. Plant the moss by pressing it into the soil. Water the
terrarium, screw the cover on, and place it in a shady place. If it seems
too wet, leave the lid off for a few hours to allow some of the water
vapor to escape. Eventually you will get the balance of water just right,
and the moss should thrive. The terrarium should sustain itself for
several weeks or months without needing additional water if the lid is
kept tightly on. If conditions are just right, the moss may eventually
send up little stalks. Some of these stalks form spores that will fall to
the soil and germinate into new plants.

The January 2007 issue of Better Homes and Gardens has an article,
“Pleasant Under Glass,” by Suzy Bales. Here is an abstract: The article
highlights the fragile beauty evoked by glass gardens or terrariums.
Everyday containers such as carafes and vases can make ideal terrariums.
Featured in the article is an antique terrarium that becomes a stage for
a miniature woodland garden. It has flowering Cape primrose,
rabbit’s-foot fern, golden club moss and black and dwarf mondo grasses.

The January 2003 issue of Sunset has an article by Kathleen Brenzel,
“Serene Greens,” on miniature indoor landscapes:
Presents ways in creating a miniature indoor landscapes. Use of copper
trays in Irish and Scotch moss; Dimension of the ceramic cache pots for
mini bog plants; Amount of water used for hyacinth floats.

Now on to Tolmiea. I consulted several reference books and online plant databases, but none mentioned fragrance as a quality for which this plant is known. This does
not necessarily mean it has no fragrance, only that it is not notable.

on the safety of pickled walnuts

Is it safe to eat pickles made from unripe walnuts (including hulls)? Are some types of unripe walnuts safe to eat and others not safe? I am not sure what kind of walnut is in my garden.

I am also a bit worried by articles I found online which say that juglone from walnuts can cause cell damage. Maybe I should skip this culinary adventure?

Pickled walnuts (from English walnut, Juglans regia) are a traditional British delicacy. The Royal Horticultural Society even mentions them. Alys Fowler’s book, The Thrifty Forager (2011), says the walnuts for pickling must be picked in early summer before they harden. Traditionally, walnuts for pickling were harvested June 15, St. John’s feast day. The famous 16th century herbalist John Gerard said, “the green and tender Nuts boyled in Sugar eaten as a Suckad, are a most pleasant and delectable meat, comfort the stomacke, and expell poison.”

All walnut species have edible properties, though black walnut may be more bitter than English walnut. Edible East Bay published an article by Kristen Rasmussen in summer 2015 on pickling green walnuts from a native Californian species of walnut, Juglans californica.

Anyone who is sensitive to walnuts probably should avoid the pickled ones, too. Like many plants, walnuts have both edible uses and toxic properties. If you do not consume large quantities of walnuts (pickled or otherwise), I do not think there should be dire medical consequences. Toxic Plants of North America, 2nd ed., 2013 (Burrows and Tyrl) has a section on walnut (Juglans). The main toxicity concern discussed is that to horses, and in their case, it is mainly due to the use of walnut wood shavings in horse stalls.

A word about finding random articles on the internet: Context matters, and the citation you found about cell damage is in the context of using juglone (administered in a medical research facility) to kill cancer cells. It is not the context of everyday consumption of walnuts. Reliable sources are hard to find via the internet, and I would view with skepticism any site that is primarily commercial and does not cite trustworthy sources.

I could not find any references to the effects of pickling on the chemical composition of walnuts. Certainly, pickling (like any form of food preparation) will have some effects on nutrients. But since pickled walnuts are likely an occasional snack and not a staple upon which one’s diet is founded, there is no cause for concern.