Alpines for morning sun only

[Lori S.]

I was asked a question that was beyond my ability to answer, but if I would like to post it here, to draw on the vast experience of SRGC forumists, if I may:

What alpines would be suited to a tufa bed that receives morning sun only?  (This would be in Calgary, so cold hardiness is a consideration.)

Thank you in advance for any advice.

[Carlo]

Lori,
A key consideration would be: how many hours of sun? Most authorities consider 6 or more as a "full sun" situation. In such a case nearly any sun lover can be grown. Morning sun is generally considered better than afternoon sun in terms of exposure for an extended period of time.

If you're talking less hours than 6, your options drop--although there are plenty of wonderful plants for shaded rock gardens (note that your use of the term "alpines" is more restrictive than rock garden plants. Alpines, plants that grow above the timberline, generally require the most sun of all rock garden plants.).

[mark smyth]

I positioned troughs last year and planted them with plants to suit the conditions.

No sun
some sun only at the peak of the year
sun only a.m. in summer, none in winter
full sun

all are working fine so far

[Lori S.]

Carlo, I will have to ask how many hours of sun the site would get.  I assumed true alpines were of primary interest, but I will have to check on that, as well. 

Mark, so what species did you select for your "a.m. sun" trough? 

[mark smyth]

Heptaticas, Trilliums, Galanthus, Hostas, Crocus, small Primulas

[Lesley Cox]

And always remembering that very few plants, even high alpines are ABSOLUTELY rigid in their requirements. Most are adaptable.

[Lori S.]

Yes, my own natural impulse would be to plant whatever I could lay my hands on that was of interest, and to let the plants tell me whether the conditions suited or not, but it seems most gardeners here are rather more cautious... (or more disciplined, or smarter, or whichever  ). 

Mark, needless to say, I should have asked right out what you planted in the other not-full-sun situations too!

[Lori S.]

The answers:  4 to 6 hours of sun, and not necessarily true alpines.

[David Sellars]

What alpines would be suited to a tufa bed that receives morning sun only?

Saxifrages would love those conditions, particularly the tufa.  Most saxes do not like full sun and they would appreciate the afternoon shade.  A mix of Kabschias and Silver saxes would work well with the Kabschias flowering early and the silvers later in the spring.  If the saxes are planted directly in the tufa, the afternoon shade would be essential.

[mark smyth]

In my semishade troughs I have trillium rivale, the little ovatum and pusillum. Some small ferns, Eranthis cultivars. Primulas and Dactylorhiza