"little volunteer" tulip tree or maybe a flowering pear.

Hawthorn (Crataegus submollis), Allegheny Serviceberry (Amelanchier laevis), Crabapple. All three have fruit to extend their seasons of interest. Or Eastern Redbud (Cercis canadensis).

I don't know about the 5 year plan for cercis survival, even it is "canadensis." '71 is zone 5....I think that's on the border of hardiness or one unusually cold winter could do damage. Am I completely wrong on this?

'71 didn't mention crabapple but one has to do the background check for blight resistance on any crabapple considered.

I think you'd be considering kousa or kousa hybrids: flowers after the main spring flower glut, good bark as it matures, nice siloulette, berries. It is indeed a 4 season tree. It has a low branching habit so that might not work right in front of the house.

If you consider a magolia, keep in mind their flowering time. Too early and a late frost gives you tree mush. You might consider a yellow, just to stand apart from the crowd. But pink would look lovely against your house.

You've got a lovely big property. You could purchase some saplings this fall for next to nothing and begin your arboretum with maples, beech, oaks....around the perimeter. Dig some holes and plop them in. No soil amendments recommended, no fertilizer. All you have to do is water through November and next year. Why waste a year?

Others will be posting more unusual possibilities but I wanted to throw in my comments on the ones you're considering. As long as you don't pick something that is destined to die or disappoint you've got room to play.

Visit O'Donal's Nursery in Gorham, Estabrooks in Yarmouth, or another well-stocked nursery within a reasonable distance. Websites are great, but there's no substitute for seeing what's available in person. A visit to the Coastal Maine Botanical Garden in Boothbay would suggest dozens of possibilities as well. From there it is a matter of personal taste, although both redbud and most flowering cherries are pretty iffy for Z5. With the space you have, one suggestion that comes to mind is magnolia Lyle's Legacy, a fully double star magnolia bred in Maine and named for the late Lyle Liitlefield, long time professor of ornamental horticulture at the U of Maine. If spring flowers are not an important attribute one of the weeping katsura trees or a metasequoia in either the green or yellow foliaged forms or a copper beech would supply the year round interest you want.

Redbud should be fine for zone 5. When I moved to WV over 40 years ago, we were a solid zone 5, and redbuds are native to the entire area. Now we're zone 6.

I think a beautiful Serviceberry would look great there. It would erupt beautifully in fall and provide you plenty of bird watching opportunities with its fruit. Serviceberry or winterberry would be beautiful.

You have a beautiful home and a lovely property!

I have no suggestions for trees, but your rocks look strange to me sitting up like monuments. I would lay them on their sides. Love your house and the setting.

Most everything that has been suggested so far is quite small. I'd be thinking of flowering trees that are about as big as the trees in the background. Sophora japonica, for example or catalpa.

How about something naturally hardy--native. Native trees can help birds and help support important wildlife. I saw the most beautiful crabapple tree the other day. It flowers but also has bright red fruits as cheerful as flowers. I sure wish I had the space for one.

mad_gallica: Most flowering trees are small. Catalpa are an interesting option. Would Tuliptree (Liriodendron tulipifera) work that far north? Sweetbay magnolia (Magnolia virginiana)?

Bio Diversity: Crabapple are beautiful but they aren't native to Maine. Most common varieties aren't native to North America.

Brandywine and Scarlet Brandywine variety crabapples produces beautiful double-flowered blossoms. It is almost like roses growing on a tree. Raintree nursery also carries a variety called 'Pink Cloud'.

There are several cherry blossom varieties that can get to be quite big.

edlincoln: Neither liriodendron nor magnolia virginiana are at all likely to do well in Maine. There are a very few of both species growing here, but they tend to be near the coast where winter temperatures are moderated. Crabapples are very disease prone here. By August they all look pretty ratty from scab, codling moth, etc. unless regularly sprayed. As for attracting and feeding wildlife, large areas of southern Maine are plagued by an overpopulation of deer. About the last thing any gardener wants is a crabapple that will attract them to his or her property.

Here are my reflections on some of the suggestions given above based on my experience right on the edge of zone 4-5.

Redbud: I looked long and hard for one of Bailey Nursery's Minnesota strain of redbud. It's been in place about 10 years, and has done well when temperatures have gone below -20. I wouldn't plant any of the other types since they won't do well in New England based on the ones I've seen planted

Kousa dogwood - I have a couple of these, and while I haven't checked the one that's 1/2 mile from the house, the one behind the house is half dead after last winter's -22. It right now is a matter of waiting to see how well it recovers over time - it will need some severe pruning this fall now that i know what is truly dead. I wouldn't put one front and center in a zone 5 yard unless you don't go below about -18 or can find a selection that has a reputation for being hardier than average Kousas.

There is a large tulip tree on the campus of UNH (Durham, NH) in zone 5b that is healthy and wasn't bothered by last winter's temperatures. So it is possible, depending on where you are in southern Maine.

I like the idea of a late-blooming Magnolia, or I know of several Stewartia pseudocamellia (mine is v. Koreana) in zone 5. While the bloom isn't overwhelming, it is nice, and the tree also has lovely mottled winter bark and gorgeous fall color.

Although they aren't flowering, I am particularly partial to 3 of AKAMaine's suggestions: weeping Katsura has beautiful form and the fall foliage smells like cotton candy; a copper or deep red beech has wonderful bark, a nice form and incredible foliage all season; Metasequoia/dawn redwood is a deciduous conifer with interesting bark and form, and coppery fall color - Ogon has goldish foliage.

In addition to the Coast of Maine Botanical Garden, I am fairly sure that there is an arboretum on the campus of U of ME, Orono, that may be helpful.