Leaves on "flower" beds - Ask Extension
I live on two acres of mature oak. In fall my husband blows leaves off driveway that end up in our flower beds, which because of shade are mostly fern...
Knowledgebase
Leaves on "flower" beds #889988
Asked November 18, 2024, 11:26 AM EST
I live on two acres of mature oak. In fall my husband blows leaves off driveway that end up in our flower beds, which because of shade are mostly ferns, but some ginger, mallow. Is possible for leaves to be too deep, say 6-8" or so for overwintering? Some of the ferns seem to make it through most of the winter. If OK, when in spring should I clean the leaves out? Thanks! Also speaking of mature oak, the acorn situation on our property appears to be dire...must be bad for the deer and squirrels.
Anne Arundel County Maryland
Expert Response
Six to eight inches sounds fine, as leaves degrade quite a bit by spring. Our native woodland ephemeral species (those that regrow in spring, bloom, and go dormant again before summer once the trees above them leaf-out fully) make do just fine with piles of leaves that fall onto the woodland floor each year. In fact, the leaf layer insulates them better than a lack of leaf layer would, both in terms of temperature and slowing-down evaporation of moisture from the soil surface from dry winter air. We are not aware of any scientific studies that have researched exactly how deep of a leaf layer is too deep for certain species, but that would be hard to accomplish anyway since many other factors influence plant winter survival and long-term health.
For wildlife value and ecosystem support, leaf litter should never be cleared away, though there also wouldn't be much left to move away come spring or next summer, since it's self-composting the entire time by way of soil microbe and soil-dwelling invertebrate activity. (If it doesn't, that might indicate poorer soil health, perhaps due to compaction, over-exposure to fertilizer or pesticides, or some other factor.) If it has to be moved aside for some reason, late spring is probably the safest time if you can avoid breaking off tender new perennial growth in the process.
When you mention that "some of the ferns seem to make it through most of the winter," does that mean that some die out and don't regrow in spring? If so, maybe it's a soil moisture/drainage issue, and some non-native ferns are also barely winter-hardy in our area, or emerge too early in spring and get damaged by a late frost/freeze. Very few ferns are evergreen, so it's normal for many otherwise-healthy plants to look bedraggled going into winter and eventually lose whatever green growth they have left before spring. Even the evergreen species, like Christmas Fern, can look tired and not very green by the end of winter before the new fiddleheads emerge and unfurl. Leaf litter shouldn't cause any issues with smothering any ferns, though.
Oaks naturally have on and off years for acorn production. "Masting" is when they synchronously produce a heavy acorn crop, and they can take more than a year "off" to recuperate from that energy expenditure. If their wind-pollinated flowers weren't pollinated well in any given spring, either due to wet weather keeping the pollen from drifting to other trees, or late frosts killing the pollen or the flowers, then fruit set (the acorn crop) will be minimal that year. This year, all of Maryland has experienced varying degrees of drought (which still has not abated) since earlier in summer, and this is also likely factoring in to plant health, vigor, and fruiting (seed production, including nuts). A plant without enough resources to put energy into fruit production (even dry nuts like acorns still require lots of water to form) will sacrifice any unripe fruits/seeds it if needs to conserve resources. Additionally, naturally-occurring acorn-consuming insects (weevils, etc.) might have had a boom year, causing more nuts to not form or drop prematurely than in other years.
Unfortunately, overpopulation from habitat loss and degradation (such as fields or woodlands filled with invasive species that they don't eat) is having a larger, longer-term impact on deer population health than the short-term influences of events like a poor acorn crop any given year, which they have adapted to deal with since they co-evolved with oaks and are generalists with regards to what they eat (invasives aside).
Miri
For wildlife value and ecosystem support, leaf litter should never be cleared away, though there also wouldn't be much left to move away come spring or next summer, since it's self-composting the entire time by way of soil microbe and soil-dwelling invertebrate activity. (If it doesn't, that might indicate poorer soil health, perhaps due to compaction, over-exposure to fertilizer or pesticides, or some other factor.) If it has to be moved aside for some reason, late spring is probably the safest time if you can avoid breaking off tender new perennial growth in the process.
When you mention that "some of the ferns seem to make it through most of the winter," does that mean that some die out and don't regrow in spring? If so, maybe it's a soil moisture/drainage issue, and some non-native ferns are also barely winter-hardy in our area, or emerge too early in spring and get damaged by a late frost/freeze. Very few ferns are evergreen, so it's normal for many otherwise-healthy plants to look bedraggled going into winter and eventually lose whatever green growth they have left before spring. Even the evergreen species, like Christmas Fern, can look tired and not very green by the end of winter before the new fiddleheads emerge and unfurl. Leaf litter shouldn't cause any issues with smothering any ferns, though.
Oaks naturally have on and off years for acorn production. "Masting" is when they synchronously produce a heavy acorn crop, and they can take more than a year "off" to recuperate from that energy expenditure. If their wind-pollinated flowers weren't pollinated well in any given spring, either due to wet weather keeping the pollen from drifting to other trees, or late frosts killing the pollen or the flowers, then fruit set (the acorn crop) will be minimal that year. This year, all of Maryland has experienced varying degrees of drought (which still has not abated) since earlier in summer, and this is also likely factoring in to plant health, vigor, and fruiting (seed production, including nuts). A plant without enough resources to put energy into fruit production (even dry nuts like acorns still require lots of water to form) will sacrifice any unripe fruits/seeds it if needs to conserve resources. Additionally, naturally-occurring acorn-consuming insects (weevils, etc.) might have had a boom year, causing more nuts to not form or drop prematurely than in other years.
Unfortunately, overpopulation from habitat loss and degradation (such as fields or woodlands filled with invasive species that they don't eat) is having a larger, longer-term impact on deer population health than the short-term influences of events like a poor acorn crop any given year, which they have adapted to deal with since they co-evolved with oaks and are generalists with regards to what they eat (invasives aside).
Miri
Wow! Thanks for your very detailed response. Very helpful.
As for deer health, I don’t know if many have reported seeing wasting disease in deer in Anne Arundel Cty, but I did have a 2-point buck pass by me as I sat on the deck and he definitely had the zombie look, head down, massive drooling, didn’t even notice me as he slowly walked by about 10 ft. from me.
On Nov 18, 2024, at 2:13 PM, Ask Extension <<personal data hidden>> wrote:
You're welcome.
The Department of Natural Resources has collected data on Chronic Wasting Disease, so you can inquire with them as to telltale signs and how to report a animal suspected of having the condition. The linked page is a long one, but at the bottom in the "how you can help" section there is a phone number for reporting. Alternatively, you could inquire with wildlife biologists at the DNR via an email sent to <personal data hidden> (especially if you want to share photos). Their general Wildlife and Heritage Service phone number is the same number as the one in the page above. The phone line is staffed during regular business hours, 8:00 am to 4:30 pm, except state holidays and weekends.
Miri
The Department of Natural Resources has collected data on Chronic Wasting Disease, so you can inquire with them as to telltale signs and how to report a animal suspected of having the condition. The linked page is a long one, but at the bottom in the "how you can help" section there is a phone number for reporting. Alternatively, you could inquire with wildlife biologists at the DNR via an email sent to <personal data hidden> (especially if you want to share photos). Their general Wildlife and Heritage Service phone number is the same number as the one in the page above. The phone line is staffed during regular business hours, 8:00 am to 4:30 pm, except state holidays and weekends.
Miri
