I would not choose either, because both of them are once bloomers, and if I am going to plant a once bloomer (which I have), it would be an old oldie, not a modern rose.

If I had to choose between them, I would choose Alchemist, because HMF says it gets to 20 feet tall, and I love big climbers.

Jackie

Alchymist in a heartbeat.
because there are so many pink climbers that are remontant and fragrant, and also re-bloom, but for me to choose a once a year blooming rose it has to be a rose that cannot be duplicated in color and form and beauty in the remontant classes. I see Alchymiist as such a rose, it's color and form are very special and it has attractive foliage too.
Where we live, several miles from San Francisco, Ca Alchymist does re-bloom, and quite well.
In spring it blooms fully
In summer it produces 4 to 5 blooms per square yard of plant.
In the autumn it produces a good flush, nearly the equal of the spring flush.
I feel this is due to our long growing season, roses bloom here 9 to 10 months of the year, and the fact that one of Alchymists parents' was a Florabunda; short pedicles influence the speed of re-bloom if the genes for remontancy are there. Even if I lived in a cold climate where Alchymist does not rebloom I would consider growing it for its' uncommon color, lovely form of bloom and pretty foliage.

Luxrosa

Alchymist for me. Grows like a pillar rose and although it only blooms once, it is a vey long bloom time in the PNW
The flowers start out a rich shade and as they fade the colour is still pleasing.

Same picture a week later and still fresh. Constance Spry is beautiful but I am not fond of a myrrh scent.

I have planted them both, and both are still quite young here.

I've seen Constance Spry at Mottisfont, and it knocked my socks off. I've seen pictures of Alchymist, such as the one in Carol Meyer's garden; incredible. Both seem lovely beyond description.

If they suit your climate, I don't see how you could go wrong with either.

Folly

"If they suit your climate"....
I wanted 'Alchymist' until I saw it once at the nursery La Campanella in northern Italy. It was a horrible sight, like nothing I've ever seen before or since: a mass of dried shriveled blooms from the early summer hot weather and the sun, the entire plant covered, the entire flowering ruined. Australia suggests hot and dry to me, though I don't know your garden. This is a cool-summer rose, or one that, in a hot dry summer climate, needs part shade and some freshness in the period when it blooms.
I like 'Constance Spry' quite a bit, but don't know what its climate needs are.
Melissa

Melissa'a comment makes me wonder about a couple of things. First, about Alchymist. Is it considered an early, normal or late bloomer? And secondly, I'm sure that climate affects blooming period for once bloomers also, I'm just wondering to what extent. I live in a climate with much milder winters than N. Italy (much more different than the slight difference in latitude would explain) but with summers of more or less similar fierceness and I've seen Alchymist blooming in April / May without particular problems as the one's Melissa is describing. Maybe it is much more of an issue in a climate where the winter is harsher causing the plant to bloom later when the harsh Med summer has already arrived? Having said this, I'm sure that this particular rose can be a good candidate for a NE facing wall in a warm climate.
Nik

This post was edited by nikthegreek on Sat, Feb 15, 14 at 1:15

The first one mildewed for me whereas the second one had no black-spot in an Oregon collection I visited that had numerous other kinds of roses right around it that did have black-spot.

Even in my climate with a multiple month spring that lasts into July and a cool summer once-blooming roses with well doubled flowers may often have many of the flowers shrivel or even abort starting in late spring. I really think this is due to the drying of the soil on many sites that has been underway for months - despite the continued precipitation. When I had an assortment of old European roses there developed this annual bore of waiting for the peak bloom only to have a bunch of the flowers and buds go down in this way, making the growing of them kind of pointless (so to speak).

Besides the inspiration of Constance Spry growing at Mottisfont with its mild English summers, there is also the inspiration of the planting Steve Jobs did at Pixar Animation Studios in Emeryville here in California. I had wondered if this planting had survived, but the date on the article below is December 2012, so perhaps it has, at least until a year ago.

Folly

Here is a link that might be useful: Constance Spry at Pixar in Emeryville

I only grow Constance of those two and I love her. Haven't grown Alchemist. Here being a once-bloomer is not a bad thing because we get Japanese beetles that ruin most summer blooms. She blooms early for a few weeks totally covered in blooms. She is very vigorous and healthy. Her blooms are large and I like the myrrh scent blended with honey better than some other myrrh-scented Austins.

We had a severe tropical storm several years ago and the trellis Constance was on tore apart with the winds and there was flooding in my garden that killed many perennials. She survived, I had the trellis rebuilt and cut her back and tied her to the replacement structure. The next year she bounced back and didn't miss a beat with her bountiful blooms. She's a survivor.

Now, I want both! LOL They're both beautiful and would be lovely if we can start growing climbers :)

Bboy, when I lived in western Washington state a portion of the buds on some of my old roses used to abort regularly, though the remaining bloom was still gratifying. I don't have this problem of aborting buds on my old roses now. Could it have to do with the heavy soil here, the retains the moisture better? I don't water, and the roses bloom when spring is turning into summer, just as they did in Washington.
Melissa

We live in eastern Washington and don't have any problems like that...maybe because more snow, less rain? If they make it through the winter, the old roses look great in late-May, early-June...when they finally bloom, here :)

Thank you all for the input. Decided to go for the Alchemist because I love those pics that Lynette had posted. I hope Alchemist is fragrant.

My two Alchymists were very fragrant. This is not a climber that starts blooming right away. Both of mine seem to wait after other climbers have already started. It is a Kordesii rose so both cold and heat won't stop it from performing well. One more photo to push you over the edge!!

Melissa- i joined this form, so i could comment your experience with Alchemist in La Campanella. I fell in love with this rose after seeing photos of this gorgeous rose in this nursery. Member of our rose community posted these photos in our local rose forum after her visit to the nursery. They are simply stunning. I live near Gorizia where it gets pretty hot in the summer. I just planted this rose and i really hope that Alchemist will prosper in my garden.