Pick of the Hydrangeas, with Adam Wheeler – A Way to Garden with Margaret Roach – July 27, 2026

Adam Wheeler, who runs production at Broken Arrow Nursery in Connecticut, spent about 25 minutes with host Margaret Roach walking through hydrangea species, pruning basics, and cultivars worth knowing. Not a news story. Useful if you grow these plants or want to.

The one rule that matters most

Before you cut a hydrangea, know whether it blooms on old wood or new. Old-wood types, including the common big-leaf Hydrangea macrophylla, set next year's buds on this year's stems. Cut at the wrong time and you've removed the bloom for the following season. Wheeler's guidance: prune as little as possible, and do it early in the growing season. Panicle and smooth hydrangeas bloom on current-season growth and are far more forgiving.

Where the breeding has gone

Panicle hydrangeas (H. paniculata) have seen 50 to 60 new cultivars come to market in the past decade alone. Wheeler highlighted Daruma, which tops out around six feet after 15 years, and Yuki Gesho, a Japanese selection with heavily marbled white variegation that works well in shade.

For big-leaf hydrangeas, the development worth knowing is remontant varieties, cultivars that bloom on both old and new wood. One hard winter no longer wipes out the season entirely. Wheeler singled out Lady in Red, a lace-cap with red stems and fall color, and New Wave, which carries bold leaf variegation. Flower color, pink versus blue, still tracks soil pH.

Species that may be hardier than the references say

Wheeler flagged H. aspera, the rough hydrangea, as considerably hardier than most literature claims. Published ratings put it at zones 7 to 8; Wheeler said Broken Arrow has seen it perform in zone 6 and possibly parts of zone 5. Worth noting: Wheeler works for the nursery selling these plants, so the claim carries a commercial incentive. Treat it as encouraging nursery-trial evidence, not settled guidance. If you're in zone 5 or 6 and want to try it, ask your cooperative extension or a regional botanical garden that has actually grown it through your winters.

H. serrata, mountain hydrangea, is closely related to big-leaf but one full hardiness zone tougher. Oak leaf (H. quercifolia) runs eight to ten feet, tolerates zone 5, and offers exfoliating bark and burgundy fall color alongside the summer flowers.

On the season

Roach mentioned her mature panicle hydrangeas were barely budding in mid-July, weeks behind. Wheeler said he's hearing that across the board. His read: there is no normal growing season anymore, and every year arrives with a different set of problems.

Broken Arrow begins taking mail-order for fall shipping in late summer, which is the relevant window if any of these cultivars are on your list.

Host Margaret Roach and Adam Wheeler of Broken Arrow Nursery in Connecticut spend about 25 minutes touring the expanding world of hydrangeas — species, cultivars, pruning basics, and some lesser-known options worth tracking down. Light on practical urgency, rich for anyone who grows or wants to grow hydrangeas.

What was covered

• Pruning fundamentals: Adam Wheeler explained the single most important thing to know before cutting a hydrangea — whether it blooms on old wood (last year's stems, like the classic big-leaf Hydrangea macrophylla) or new wood (current season's growth, like panicle and smooth hydrangeas). Old-wood types: prune as little as possible, and do it early in the growing season. New-wood types: far more forgiving.
• Native American species: Wheeler walked through H. arborescens (smooth hydrangea, native from Connecticut to Alabama, zone 5-hardy) and H. quercifolia (oak leaf, southeastern native, eight to ten feet tall, four-season interest including exfoliating bark and burgundy fall color). Newer cultivars beyond the familiar Annabelle include Hayes Starburst (double-flowered), Green Dragon (heavily serrated leaves), and Little Honey (compact, gold-leafed oak leaf).
• Panicle hydrangeas (H. paniculata): Wheeler estimated 50–60 cultivars have come to market in the past decade. Highlights: Daruma (compact, tops out around six feet after 15 years, early bloomer) and Yuki Gesho, a Japanese cultivar with heavily marbled white variegation that brightens shady spots.
• Big-leaf hydrangeas (H. macrophylla): At least 300 varieties exist. The most practical development for gardeners: "remontant" types that bloom on both old and new wood, reducing the risk of losing the season after a hard winter. Lady in Red (lace-cap, red stems and fall color) and New Wave (bold variegation) were singled out. Flower color (pink vs. blue) still tracks soil acidity.
• Lesser-known species: Wheeler flagged H. aspera (rough hydrangea) as hardier than most literature claims — zone 6, possibly zone 5, despite being widely listed as zone 7–8. H. serrata (mountain hydrangea) is closely related to big-leaf but a full hardiness zone tougher. H. angustipetala selection Monlong Shoe has sterile florets nearly the size of a palm and carries a hint of yellow pigment — unusual in the genus.
• Climate irregularity note: Roach mentioned her very old panicle hydrangeas were barely budding in mid-July, weeks behind schedule. Wheeler said he's hearing similar reports and no longer considers any growing season "normal."

Notable claims & predictions

• Adam Wheeler on old-wood pruning: "The general recommendation is to try to prune as little as possible… prune with caution. And the pruning work is best done early in the growing season." Applies to H. macrophylla, the most commonly grown type.
• Adam Wheeler on H. aspera hardiness: "A lot of the literature is just completely inaccurate relative to how cold-hardy these plants can be. Most literature says they're zone 7 or zone 8. But we've seen them performing certainly in zone 6 if not in parts of zone 5." A meaningful upgrade for gardeners in colder climates who may have written off this species.
• Adam Wheeler on remontant big-leaf hydrangeas: Newer varieties that bloom on both old and new wood represent "a really exciting advancement" — the practical payoff is that one bad winter no longer wipes out that year's blooms entirely.
• Adam Wheeler on climate: "I've come to accept that there is no normal consistent growing season that we're navigating anymore. It seems like every year is giving us a different set of curveballs."
• Adam Wheeler on Broken Arrow's mail-order schedule: "Late summer… we start taking orders for fall shipping" — relevant if you want to order any of the cultivars discussed.

Fact check

• Wheeler's claim that H. aspera is hardy to zone 6 or even zone 5, contradicting most published zone 7–8 ratings: This is presented as observation from nursery trials, not a peer-reviewed finding. It's plausible — microclimate, provenance, and siting matter enormously — but Wheeler works for the nursery selling these plants, so there's a commercial incentive to expand the perceived hardiness range. The claim isn't false, but treat it as encouraging preliminary evidence rather than settled guidance. If you garden in zone 5 or 6, ask your local cooperative extension or regional botanical garden before investing heavily.
• Wheeler's statement that H. macrophylla "traditionally flowers only on old wood" is well-established and accurate. The remontant exception he describes is also real and widely documented in horticultural literature.
• The 300-plus varieties figure for H. macrophylla is consistent with what commercial breeding databases show; no reason to dispute it.

No claims rise to the level of false or clearly misleading.

Why this matters for you

• If you already grow big-leaf hydrangeas and they fail to bloom most years, the remontant cultivars Wheeler describes — which flower on both old and new wood — are a practical fix worth exploring before next planting season. Ask at a well-stocked independent nursery or check Broken Arrow's mail-order catalog when fall ordering opens.
• Pruning timing is the most common and most damaging mistake with hydrangeas. The old-wood/new-wood distinction Wheeler explains is the rule to internalize: cutting a macrophylla at the wrong time removes next year's buds entirely. If you've been guessing, this episode gives you the framework to stop.
• Gardeners in zones 5–6 who assumed oak leaf or rough hydrangeas were out of reach may have more options than standard references suggest — worth a conversation with a local nursery that has actually trialed these plants in your region.
• Practically speaking, this episode is interesting but nothing to act on this week unless you are actively planning a fall plant order or troubleshooting a hydrangea that hasn't bloomed.