I have hundreds of feet of large lilacs in three different groupings. We have just experienced an epic flood on May 10. The lilacs were under 3-4 feet of water for a week. Massive amounts of debris up to 4 feet high and unknown possible contaminants. In addition the water was very fast and carrying significant amounts of sand. In one grouping the sand left behind was up to 2 feet deep. Each group required labour intensive removal of debris hanging on all branches-mostly grass and mud balls. This, plus the sand all had to removed manually. Days of work. One grouping (the one with the most sand) is completely dead, all leaves are brown and curled up. However, if you scratch the bark, it is still green underneath. There is also a seemingly dead and very large Sumac in this group and scattered roses and dogwood which flowered and look quite healthy. The other two groupings are not completely dead. In one, about half the trees are on the way out-still some green to the leaves but curling and fading in colour. This group seems to be increasingly deteriorating. The final group is the furthest from the river and would have had the slowest water as it is protected by the house. This group appears to be overall healthy but a few deaths here and there. Could it be a lack of oxygen in the soil? Water covered too long? The debris stripped everything off up to 4 ft. - not enough leaves? Stress? Please help! This hedge is a screen from the neighbours and a deer barrier-about 15 feet high.
You folks had a horrible go of it this spring :-( I wish the 1948 story of the flooded lilac gardens in Woodland, Washington, indicated whether the lilacs were underwater for an extended period of time or simply washed away: http://www.lilacgardens.com/about/history/ The Univ. of Guelph Arboretum seems to suggest these are flood-intolerant: Lilac Collection | The Arboretum , and that seems to be the consensus from glancing through other sites. That suggests the lack of oxygen from being covered by water for too long will be the culprit. It doesn't sound like there is too much hope, but there wouldn't be too much harm in leaving anything with green underneath the bark for a year.
I agree w Daniel // I know of really old lilacs in the Okanagan way up the mountain along the KVR trail They’ve been thru forest fire and drought and ice and snow and old steam engines Granted these are the old pale purple colour - nothing fancy - but they are reliable and pretty scent If you can - amidst your many other chores - take away some sand etc from the normal root area where it meets the twiggy branches above ground - give it a try and see what transpires next spring If you have some dead ones - you could use those as a privacy trellis and grow some nice hardy clematis they them - is Clematis Montana hardy enough for GForks?
I sure can empathize with your worries about the survival of your beautiful old lilacs. Please let us know next year whether they lived or died.
Thank you for your replies. Not what I was hoping for but pretty much what I expected. I can no longer scratch the bark on group 1 so think they are all permanently dead. The Staghorn Sumac in that group is also dead, the leaves never came back. No new growth on either of these. I am currently using the Sumac as a prop for some red osier dogwood in an attempt to have some green in that whole area. In group 2 more are on the way out but I noted this week some new growth coming up through the soil on a couple of trees. Group 3 is still looking good with only one large clump deceased so far. Lots of new growth here despite these ones being buried in gravel instead of sand. The challenge is knowing when to water again. And yes we can grow clematis here. I have four-they were also in the worst area, deepest and fastest. They are doing beautifully, started new growth shortly after the flood receded and I washed all the leaves. Part of the problem I think is related to how high the river still is for this time of year. So even though the river went down, the water table is still very high so drainage would be minimal. Some people still can’t dry their basements as seepage is still coming through the walls and floors. One interesting thing is that my pond which is hundreds of feet from the river has fish-river fish. Just small ones, could be trout or sucker fish or even minnow that don’t grow. How they survived the filth and current of the water followed by me cleaning with a shop vac I really don’t know. I will have to wait until they are much larger so I can capture them and return to the river. The pond also acquired a large painted turtle. I am not sure if it is still in there or has moved on. Thanks again!
