This site is for people who like plants -- growers, enthusiasts, aesthetes, novices and professionals, those who appreciate wild things and those who appreciate the cultivated. I garden in Chelsea, and I've been visiting people's yards for 20+ years in the course of my work. My goal is to make this blog a community project, so if you share my interests, please consider becoming a participant and contributing content -- Guerin. Info: greenstreet@mindspring.com

Thursday, March 31, 2011

Interesting, but it is art?



What kind of statement do you think this resident on Miller (at Gott) is trying to make with his or her arborvitaes? Looks darn cool, though!

Hazel in flower

Spotted this interesting and unusual tree along Miller Rd this afternoon. It is a Turkish hazel (Corylus colurna) and it's in full flower. I haven't seen many of these (there's an amazing specimen in the arb) but they seem to make lovely specimen trees. Attractive flaky bark, an equally attractive upright pyramidal form, and tons of wildlife food. The base of the tree on Miller (as I recall, on the north side of the 11 hundred block) was covered with hazel-nut shells.

The dangly things are called aments or catkins. You can say to people, "Ooh, look at that amentiferous action!"   And if someone asks you what you are talking about you can tell them that naturally you are referring to the spicate inflorescences bearing scaly bracts and unisexual (male) apetalous flowers. (By the way, when I searched 'ament' in the on-line Merrian-Webster dictionary, I got the above definition, followed by the question, "What made you want to look up ament? Please tell us where you heard of it."

If you look really close you can find the brightly colored female flowers. Too bad they are the size of a head of a pin. Way beyond the abilities of my cheap camera to capture adequately. 

Our native hazels have similar flowers. I used to grow the common Corylus americana in my garden. It's a plant I'm always happy to run across in the wild, but it suckers too much to be useful if you have very limited space.    

Tuesday, March 29, 2011

The best book on Woody Landscape Plants

Let me tell you: if you have to pick just one book as a reference on woody plants for the garden, it most definitely should be Michael Dirr's "Manual of Woody Landscape Plants: Their Identification, Ornamental Characteristics, Culture, Propagation and Uses."  There is nothing else that comes close. No, it doesn't have pictures, but who needs them when you can easily do a google search of images. What it does have is everything you need to know about every woody plant you are likely to encounter.

Where it particularly shines is in his observations on 'landscape value.' I don't think I have ever taken issue with any of his comments, which range from "a sickly sight in any landscape" (for corkscrew willow) to "one of the best small specimen trees I know" (for one of my favorites, Parrotia persica). It's also quite comprehensive -- for example, he describes 38 species of maple in the fourth edition, most all of which deserve a place in the Michigan landscape and most all of which are quite available.

It's a fun read. It's the book you'll see on the sales counter at Abbott's Nursery. And it's the first reference I turn to when I'm looking for a second opinion on the ornamental value of woody plants.

Monday, March 28, 2011

Phoebes and skunk cabbages

The cold weather of course has really slowed everything down, but I did see a phoebe (an early-arriving flycatcher) by Cedar Lake in Chelsea yesterday. I thought about testing what I was taught years ago about skunk cabbages -- that the developing flowers generate their own heat, such that it is significantly warmer inside the plant than in the outer environment. So I grabbed a meat thermometer from the kitchen and . . . well, please e-mail me if you fail the see the fatal flaw.

Tuesday, March 22, 2011

An unusual, early-flowering hellebore

British plant aficionados first received seed of Helleborus thibetanus in 1991, and it's slowly gotten around in cultivation since then. It flowers earlier than the common 'lenten rose,' never fully lifting its head to the sun (but not always as droopy as in this photo taken in today's rain).  As a young plant it goes dormant in summer, but established plants maintain their foliage until fall. I like showing this off to visitors since I figure they won't have it and it doesn't have a common name, so that makes me cool, right?

The ever-infallible world wide web tells me this is the lone hellebore of eastern Asia and is native to open montane forests in the Chinese provinces of Gansu, Hubei, Shaanxi and Sichuan.

When squirrels go bad !

They nip off the ends of spruce branches.

Monday, March 21, 2011

Another early spring crocus

Crocus chrysanthus is another early crocus that is showing up in gardens right now. Yellows predominate, but the Dutch have hybridized it with other species, such that there are blue and lilac selections sold under this name as well. The flowers of these 'species' crocuses are small, but they arrive about two weeks earlier than the pumped-up common commercial hybrids. Personally I prefer the delicate wild types. The one pictured is C. chrysanthus 'Cream Beauty,' or at least that's what I've been telling myself.

The worm is not my friend

I wish worms would leave my garden alone. They eat the compost that I mix into my sandy soil. They leave behind water-repelling worm casings, leaving a 'soil' that resembles a fine-textured grape-nuts cereal with the absorbency of plastic. The ONLY way to wet my soil then is via slow drip -- water from a hose goes right through it all the way to China.

I've heard that I'm no longer the only one who recognizes the down-side of these non-native squirmies. People who fish up north are being urged not to toss their unused worm-bait into the surrounding shrubbery. Escaped worms will decimate the soil humus, and there go the wildflowers.

Sunday, March 20, 2011

More about cyclamens

Cyclamens make wonderful early-flowering garden plants in Michigan. Here's a picture of another one from my garden as it appeared this weekend. It's growing in half-shade in sandy, droughty soil. I've done nothing special to care for it, and this year it didn't even benefit from a cover of mulch -- although it helped that there was a good snow cover. One winter, one particularly long cold winter more than 10 years ago, all my cyclamens rotted and I had to purchase some replacements. On a plus side, they gently seed around by themselves in the garden, and gathered seed will readily germinate indoors.

I've heard some authorities recommend that the bulbs be planted deep, 12" or more, but I haven't followed that advice. But nor have a I tried any species other than the common spring-flowering Cyclamen coum and the fall-flowering C. heterophyllum.

As is the case with the Arums, the cyclamens are summer dormant, which is not uncommon for plants adapted to a Mediterranean climate.

Friday, March 18, 2011

Hybrid witchhazels in full bloom

close-up of strap-like petals
There's a nice planting of witchhazels at the south end of the Exhibit Museum on the U-M campus. The one with the yellow flowers has a very pleasant fragrance that travels far. I was ready to identify it as Hamamelis x intermedia "Pallida," which is the selection I grow (and cherish) in my own garden.  Give this plant five or so days of warmish weather in February or March and it will come into full bloom -- and it will retain its beauty even after the thermometer does its inevitable subsequent plunge. Browsing through images on-line, however, I realize this campus specimen could just as well be "Arnold's Promise," which got its name from Harvard's famous arboretum in Boston. Or it could be "Westerstede." Or . . .

The witchhazel with the reddish flowers is probably the hybrid "Diane." The flowers looks great close-up, but the plant in bloom is pretty drab when viewed from 6' away. All these Asian hybrid witchhazels are fantastic plants, but my experience is that they never look better than when you first get them from the nursery.  So heck, just replace them every decade or so. It's well worth it.

Thursday, March 17, 2011

The season's first hellebore

Helleborus niger: this is the first hellebore to come into flower (the photo was taken today, with me propping up one of the flowers with a short stick). For me it's more of a novelty than a thing of beauty. A more ambitious gardener might do well with this in our climate zone -- there are certainly some lovely specimens being bred and offered by Arrowhead Alpines in Fowlerville. It's a nice enough foliage plant, but you might need to experiment with placing and protecting it carefully in order for it to flower well. Some people might know it by its 'common' name, "Christmas rose."

An early and prolific crocus

This crocus opened fully in great numbers throughout my garden today. This is the best-performing of all the 'species' crocus (crocuses? croci?) I have tried. I'm fairly certain it is Crocus tommasinianus, a selection that you can buy for pennies apiece from John Scheepers (www.johnscheepers.com). The catalog speculates that squirrels don't eat it, which may be why I have such success with it.

How cool is West Park!

West Park, Ann Arbor: until just recently all this water ran through a pipe underground. I assume it connected to the Allen Creek drain that runs underground south to north through downtown. The hydrology of West Park has been restored to a more natural state, allowing water to seep into the soil and providing a habitat for the larches and sycamores that were planted as part of the restoration. A boardwalk crosses these new wetlands at various points. It's lovely. I will be very interested to see how this evolves over the seasons -- will it dry up in the summer? what kind of vegetation will establish itself? And I'm already looking forward to the spring of 2012 by which time a population of frogs will have taken up residence. Hurray, Ann Arbor!

Wednesday, March 16, 2011

Walnut trees threatened by a thousand cankers

With 60 degree weather in the forecast, we hope to move onto happier flowering topics soon . . but in the meantime, here's one more heads-up about threats on the horizon. This one is called 'thousand cankers disease.'  It affects our common and valuable black walnut (Juglans nigra). It's been known from out west for about eight years, but was identified on August 5 of last year in Knoxville, Tennessee. This is the first time the disease has been found within the native range of black walnut.  Read on . . .

Tuesday, March 15, 2011

Seriously: can you buy topsoil?

Have you ever wondered: ‘what is topsoil and where can I get me some?’ The answer is likely much more complicated than you imagine. Topsoil refers to the upper horizons of the soil profile, in which organic matter has been incorporated through chemical leaching and the ongoing activities of soil fauna and flora.

If you go to a garden center, it’s highly unlikely that what they sell as ‘topsoil’ meets that definition. Usually the so-called topsoil available for purchase is mix of sand and pond muck. Sometimes it is excavated clay that is screened and mixed with sand to give it a workable consistency. The problem with the former (other than the fact that it is not topsoil) is that organic matter will wash through or decompose within a few years, leaving plain old sand. The problem with the latter is that the sand will fill the interstices within the clumps of clay, leaving something akin to concrete. What to do, what to do?

During times of economic boom, it is often possible to purchase actual ‘topsoil’ that has been collected from sites which are being developed for homes, offices, hospital expansions, etc. Given that such economic growth is pretty nil right now, the best you can do is buy compost. If you are working with sandy soil, adding compost will give you something that will act a bit like a good loam. If your parent material is clay, adding compost will increase drainage and boost the activity of soil organisms.

These soil organisms are what turn a heavy unworkable clay into a proper rich topsoil. It is the ‘glue’ that is formed through their activities that causes the clay to develop into aggregates. This is called ‘soil structure,’ something that is lost when the soil is compacted, or that can be badly compromised by unnecessary tillage.

Some people complain about clay, but I sorely wish the parent soil of my garden included some of it. There’s only so much you can do without it. So endeth my rant. If you have insights on this most basic of garden topics, please step forward!

MSU and Extension experts share gardening advice on-line

The "Michigan landscape CAT alerts" are a great source of timely information about trees, gardens, plant pests, insect pests of the home, weather, and lots more. "CAT" stands for "crop advisory team" but you don't have to remember that. Already this year the staff (from MSU and Michigan Extension) has posted some nice articles on native trees, how to deal with ants in the home, the use of gypsum as a soil amendment and lots more. Plus you can search for articles from previous years. Highly recommended! Here's the link: http://ipmnews.msu.edu/landscape/ . UPDATE FROM 2/21: the location for the alerts is being moved to http://news.msue.msu.edu

Monday, March 14, 2011

Waiting for the next invasive pest

Don't think we're out of the woods, now that emerald ash borer has swept through. There are plenty more exotic pests at the state's borders, and who-knows-how-many more that can hitch a ride on packing materials from Asia, Africa and Europe. Two species that have the entomologists' attention are the sirex woodwasp and hemlock wooly adelgid.

Native woodwasp (or horntail) species are common and attack weakened pines and other conifers. The sirex woodwasp operates similarly in its native Europe and Asia. However, bring it to North America or the southern hemisphere, and it does a lot of damage to healthy living trees. 80% mortality has been recorded on tree plantations south of the equator. An Ohio Extension entomologist reported to a group of Michigan arborists last month that this pest is now present and active in that state, where it has been killing white pines. In 2007 and 2008, specimens were collected in Macomb and Sanilac Counties in Michigan, but we have heard of no further activity here. It's quite possible that it's just a matter of time.

Entomologists are also on the lookout for the hemlock wooly adelgid, an aphid-like insect that has been present in the U.S. since 1924. The pest has decimated hemlock forests along the east coast, and there is a quarantine underway to prevent its spread into Michigan. Since hemlock is not a particularly common landscape plant in southern Michigan, and since the pest is relatively easy to control on individual specimens, the introduction of the pest into our immediate area will only have a small impact. But up north, where hemlock is plentiful, it would represent another ecological disaster.  The adelgid has been found at least twice in Michigan, resulting in the close inspection of tens of thousands of other hemlocks nearby. It seems that so far we've been lucky.

Sunday, March 13, 2011

First flowers

You have to scooch low to the ground to the appreciate the color in this gray March weather. Cyclamen coum has sent up its first flowers; and, if the sun would shine, there would me a nice show of winter aconite (Eranthis hyemalis).