Trees and shrubs in parks and gardens 2015

[johnralphcarpenter]

A few more:

Buddleja alternifolia

Buddleja loricata.

[fermi de Sousa]

In the depths of winter we have the Mexican Hawthorn, Crataegus mexicana (also known as C. pubescens, but not by The Plantlist!), is in full fruit which the parrots don't seem to be attracted to! Bonus!
cheers
fermi

[johnw]

I was delighted to spy this tree in a local garden centre. I had no idea a dwarf Liriodendron tulipfera even existed. It's on called 'Little Volunteer'  Nice to have such a thing close to eye level where they can be seen by kids who seem quite fascinated by such leaf oddities, dwarf Ginkgos included.

john

[brianw]

Some years ago, maybe 5 or 6, in a weak moment, I bought a winter sale plant labelled Cercis chinensis ‘Don Egolf’, 2’ or so high. I was unable to plant his out at the time and unfortunately it stayed in the pot for 2-3 years, not increasing much in height, never flowered. Not the best treatment. Now planted out and in its second season it looks quite healthy and even had just a few flowers this year, well 5 actually.

The original plant structure is a quite gnarled small shrub with grey bark with currently many very healthy looking growths mostly 4 – 8” long with leaves 2 – 3” across. There has been some tip dieback each year so it does not increase in size as much as it might, and is now maybe 3’6" high and across.

But. From the base since it has been planted out, some just below the soil level, some just above, I have strong growths 12 – 18” long currently with leaves up to 4” across. The obvious conclusion, to me, is this is a graft stock suckering. Apart from size and vigour there is no obvious difference in these shoots. There is little sign of a graft joint but I can see no other obvious conclusion. Do I now have the possibility of 2 desirable plants. Which do I keep, 1 or both? Can I assume this is the species C. chinensis?

I can just cut all these shoots off and try to keep the plant with a clean stem but it would be a waste not to try and root some. Reading online this is not at all straightforward. My usual technique for most shrubby things is heel or nodal cuttings and minimise leaf area, gritty sand soil, and seal in a plastic carrier bag. Works fine for most things I try. I may get some heel cuttings from off the main stem but most will just be long very leafy stems. Never tried to root cuttings with such large leaves. Any advice welcome.

[Brian Ellis]

I was delighted to spy this tree in a local garden centre. I had no idea a dwarf Liriodendron tulipfera even existed. It's on called 'Little Volunteer'  Nice to have such a thing close to eye level where they can be seen by kids who seem quite fascinated by such leaf oddities, dwarf Ginkgos included.

Well this kid will look out for one - definitely!

[johnw]

brianw -  At a nearby garden centre we saw Cercis chinensis 'Don Egolf' the same day we spotted the Liriodendron.  I was surprised that it had sustained a good bit of winter damage, many branches had frozen back. Some Cercis canadensis here got hammered last year, not surprising as nurseries sell them indiscriminately and pay little attention to provenance - it ranges from Texas to Maine. Forest Pansy for instance lost a good 2-3ft of growth whereas northern forms flowered their heads off.

BrianE   - Always happy to keep you young bucks amused with new trees.

johnw

[Rick R.]

A dwarf Tulip tree would be very cool, but flowering age is still unknown as far as I can tell (and assuming it will flower).  Not sure that that is anything to worry about, since normal Tulip trees only begin blooming at age 15 or so (and then sparsely at the top), but just something to consider.  I am also wondering about how they estimate its mature height at only 9m, especially at the rate of growth claimed:
"After four years growth from a transplanted liner plant, ‘Little Volunteer’ achieves a height of 4 meters and a width of 2 meters, and an average trunk diameter of 60 mm."

See here for the patent application:
http://www.google.com/patents/USPP19581

Note that there is a prior, supposedly inferior, Tulip tree dwarf called Ardis (not patented).

Not that it would matter to most of you, but I might be skeptical about the hardiness rating of USDA zone 4.  It's not really been tested, parentage is unknown, and the dwarf was discovered in Tennessee, USA (zone 6-7).

[johnw]

Rick  - Dirr rates L. tulipfera as Z4 to 9 and says it is being grown at the Minnesota Landscape Arboretum and it can withstand -25F.  No idea if that is true and the Minnesota tree is still alive.  I got a variegated one for a friend in interior Nova Scotia and it has grown like a fiend, I'd say it is a cold Z5a there though it can be grown in Z5a in Montréal.  It is not as wind-tolerant on the Z6-7 coast here as it is in Z5b in the Annapolis Valley of NS where it makes a very big tree.   My thought is 'Little Volunteer' would certainly be easier to protect from gales; having said that there are some big Liriodendrons about the city.  Provenance with L. doesn't seem to be an issue here or we've been lucky.

Jack Alexander at the Arnold once told me the issue of provenance is very complicated.  He said they had no hardiness issues with Taxodium distichums collected in the Northern part of its range or with those from the deep south including southernmost Florida.  He reckoned all T. were once northern and pushed south by the Ice Age.  Provenance has been an issue for us with eastern natives Cercis, Nyssa, Liquidambar and Magnolia virginiana.

By the way a friend was at a June conference in Minneapolis and he was astounded by the size of many trees there including the Cercis. Amazing what a hot summer & fertile soil will do.

john

[Rick R.]

Of course, Dirr uses the Arnold Arboretum hardiness zone map, not the USDA's.
http://arboretum.harvard.edu/wp-content/uploads/Hardiness-Zone-Map-1967.jpg
He clearly states this in his Manual of Woody Landscape Plants along with a map of each.

As an example, the average annual minimum temperature:
Aronold Arboretum zone 4 = -20 to -10°F
USDA zone 4 = -30 to -20°F
So indeed it is no stretch for Dirr to state the Tulip tree cold hardiness to zone 4.

Under the Arnold Arborenum map, the Minnesota Arboretum is a solid zone 3 (USDA zone 4).  Tulip trees (4 or 5 of them) do thrive there, and one or two are 50 or more years old.  They are of northern provenance.  The old one(s) grow in an unmanaged natural woods, and are comparatively small for their age.  I live 9 miles west of that Arboretum, and in fact have a 23 year old Tulip tree of my own in the backyard.  Many people have tried to nurture Liriodendron tulipifera here, but not many have success.  Whether provenance is an overriding factor, I cannot say.

[johnw]

Good grief, I thought the old Arnold hardiness map went out the window in the 1970's.   I see those temps are not record lows but the average annual minimums in which case Nova Scotia is a mess based on that map. 

In the 6th Edition which I have he uses the USDA map but does not show Canada at all.  Likely his first sentence says it all......

Here's a Cercis canadensis of unknown provenance after last winter's low of 0F/-17.8c, the nearby Magnolia virginiana and Paulownia were untouched.  We replaced it with a Magnolia grandiflora 'Bracken's Brown Beauty'.

johnw

[Rick R.]

Oh!
Well if he still says zone 4 for the Tulip tree in the 6th edition, then things "have" changed!

You probably already know that the only Cercis canadensis fairly reliable here in Minnesota is the Columbia strain, sometimes dubbed the Minnesota strain or Minnesota Arboretum strain.  Its origin is actually wild Wisconsin.

[Roma]

We saw some blue sky here today

Rosa moyesii 'Geranium'

[Maggi Young]

Evidence there of how well your rose has flowered again, Roma!

[Thorkild Godsk]

Euonymus sachalinensis
A beautifully small tree or shrub
this time of year with sunshine.
Thorkild DK.

[Maritfri]

Hei!

Hamamelis has started blooming and first out is Hamamelis x intermedia 'Jelena' that I bought this spring. I am very happy with the color of the flowers



Marit