Spring leafing, the sequel
A lot of our plants have taken a hit in the wacky, up-down-up-down spring weather we’ve had this year.
Thin-leafed trees, shrubs, and perennials – lured into premature awakening by the sustained late-winter warmth – got zapped by a return to sub-freezing cold in April, while gardeners who jumped the gun on planting summer flowers and vegetables got a Mother’s Day present of wilted blobs after a 30-degree night on May 10.
Fortunately, plants once again are proving their tenacity and will to survive. The majority of injured plants have simply shed their first try of frosted leaves and grown a new set.
That’s not an ideal thing – having to spend energy on two sets of leaves in one year – but it’s better than dying, which many gardeners feared when they saw so much browning and wilting after the late-April/early-May cold spell.
One of the best examples is big-leaf hydrangea. This popular landscape shrub with the softball-sized pink or blue early-summer flowers took one of the worst cold hits – brown, wilted leaves and even dead branches down to the ground (some of which resulted earlier in winter).
Most hydrangeas are bouncing back nicely now. Even ones that appeared to show no sign of life have mostly pushed new growth from low on the bare branches and even from around the base of the plants.
These may not bloom this year if all of the last-fall-formed flower buds died, but at least the plants should “bush out” and recover reasonably well the rest of the summer.
There’s not a lot you need to do in cases like this, although it’ll help recovering plants to keep the soil around them damp if we get into a hot, dry summer, and to give them a scattering of compost or a balanced, granular, organic fertilizer.
If you haven’t done one lately, a soil test will tell you exactly what nutrients your soil might be lacking (if any) and what kind and how much fertilizer to use.
Although it’s not necessary for the health of the plant, something else you might do is pick off or snip off dead foliage.
A good example of that is the common shade perennial, hosta. These leafy plants also took a blow in the cold – suffering partial to total wilt-backs.
Hostas have widely bounced back in the warmth of the last few weeks, growing fresh new leaves that are overtaking the brown, damaged first set. Go ahead and snip out the damaged foliage back to the main crown, if you like, to neaten the look of the plants.
You can do the same with other trees, shrubs, and perennials that are still sporting brown leaves amid the new ones. The brown ones eventually will fall on their own as the new leaves grow, but if you’re neat and have the time, pick away. This dead foliage will make a decent addition to the compost pile.
As for trees and shrubs that still have bare branches or, more often, bare branch tips, give them another couple of weeks.
Odds are the wood is dead, but by waiting until the end of June, you’re giving the plant every last chance for a late comeback.
Two more “death tests” are to scrape a little bark off of bare wood to see if there’s any green underneath (green is promising, brown is bad) and to try bending the branches (flexibility is good, snapping off is bad).
If there’s no sign of life by the end of June, it’s fine to cut back dead tips to just above live growth and/or to remove dead branches altogether.
Crape myrtles, redbuds, the aforementioned hydrangeas, and Japanese maples are four woody plants that may have suffered more than just leaf damage.
Some Japanese maples have died to the ground – possibly a lingering effect from the past two rainy seasons in poorly drained spots and/or from disease. But some gardeners saw their second set of Japanese-maple leaves freeze on Mother’s Day after the first set bit the dust in April. Apparently, two strikes and you’re out is the rule for that species.
And finally, gardeners who didn’t immediately yank their badly wilted summer flowers and vegetables after the Mother’s Day freeze have been rewarded – in some cases – with recovered plants.
Plants such as marigolds and tomatoes might show their displeasure after frosty nights, but they often send out new shoots from dormant buds lower on the stems.
The fix there is to wait and see if new growth occurs.
If it does, just snip off the higher-up dead tissue and let the new bottom growth take over.
If you’re still waiting for that wilted tomato to come back from the May 10 freeze, though, it’s time to give up. It’d be a miracle rebirth now.
Make your own lanternfly trap
Now that the spotted lanternfly has made its way into most of south-central Pennsylvania, more and more home gardeners are likely to encounter this latest Asian-imported plant-eater.
One way to tell if lanternflies have found your yard is by installing traps on a few trees.
Penn State Extension has come up with a new make-your-home trap using common household materials, such as a window screen, milk jugs, a plastic zip-up bag, and some tape and glue.
Not only is the trap cheap and fairly easy to make, it doesn’t use any sticky materials, which the other main type of trap uses and sometimes captures off-target birds and harmless creatures.
The DIY trap takes advantage of the lanternfly nymph’s habit of climbing trees in search of food.
This youthful, crawling stage of the bug is easily captured when trees are “banded” with fly-paper-like traps using commercially available gum resins or even petroleum jelly.
When the crawlers step onto the goo, they bog down and die on the bands.
Penn State recommends loosely wrapping the bands of those with a protective sheet of screening or chicken wire to head off “bycatch” of birds, bats, beneficial flying insects, and such.
The new trap uses a different strategy of directing the upward-crawling bugs through a tunnel of screen and taped-together milk-jug tops and into a plastic bag, where they die in Ziploc Prison.
Penn State Extension lanternfly expert Emilie Swackhamer has posted a detailed rundown with pictures on how to make one of these goo-less traps.
This type of trap was originally designed to collect pecan weevils, which also climb up tree trunks.
Penn State says the traps can be used on any potentially infested tree, although they work best on species with smooth bark.
Lanternflies are especially drawn to trees of Heaven (the weed tree with the lance-like leaves that people often mistake for sumac) as well as walnuts and willows.
The traps are most effective from mid-spring to early summer when lanternflies are in the crawling nymph stage.
By July, the nymphs begin morphing into flying adults, which are inch-long bugs with a distinctive set of orange-red spotted wings when the wings are fully open.
Spotted lanternflies have now been confirmed in 26 Pennsylvania counties, including Cumberland, York, and Perry as well as Dauphin, Lancaster, and Lebanon, where lanternflies already were known to be prior to this year.
- Read more on the spread locally of spotted lanternflies
- See Penn State Extension’s web page on identifying spotted lanternflies
Seeing pink in the lawn?
If you notice patches of your lawn that seem to have pinkish-red blades, you likely have a case of red thread.
This is a common lawn fungal disease that crops up in late spring, mainly when daytime temperatures hover around 65 to 75 degrees and it’s been rainy or humid.
If you look closely, you’ll notice the grass blades themselves aren’t turning pinkish-red – it’s stringy fungal growths called “hyphae” that are growing onto and over the blades.
Don’t worry about this disease killing the lawn or harming people or pets. It’s not toxic, and it usually infects just the grass blades and not the crown itself, where new growth emerges.
When warmer, drier weather takes hold, red-thread symptoms (and the brown blades that ultimately result) typically fade away on their own.
Penn State Extension says under-fertilized lawns are more prone to red thread and a similar disease that’s also popping up now called pink patch. Pink patch is recognizable by the little pinkish, fluffy growths on grass blades.
If you haven’t fertilized lately, adding a high-nitrogen lawn fertilizer should help speed up the demise of both of these diseases.
Perennial ryegrass and fescue are types of grass more prone to red thread and pink patch than Kentucky bluegrass, according to Penn State Extension, as are inferior varieties of any grass.
Higher quality grass seed, which you can gradually add by over-seeding your existing lawn each fall, is a good way to reduce future outbreaks of red thread and pink patch. So is getting on a regular lawn-fertilizer plan.
Penn State Extension doesn’t recommend using fungicides on outbreaks but says that flutolanil and azoxystrobin are two that have tested effective in short-circuiting red thread and pink patch.
- More when-to-do-what tips: George’s “Pennsylvania Month-by-Month Gardening” book