# Smooth-bark St. John's-wort (Hypericum lissophloeus)

> A Florida Panhandle rarity for pond edges, with silvery bark that peels like a birch's and bright yellow flowers from May until frost.

Also called smoothbark St. John's-wort, silverbark St. John's-wort. Category: Native Shrubs. Grown from seed by Blue Whale Trees. Web version: https://bluewhaletrees.com/plants/smooth-bark-st-johns-wort/

## Facts

- Type: Shrub
- Mature height: 6 to 10 ft
- USDA hardiness zones: 7 to 10
- Grows wild in: Sandy barrens, swamps and wet flats
- Native range: Florida
- Sun: Full, Part
- Soil moisture: Wet, Average
- Growth rate: Medium
- Traits: Rare, Evergreen, Showy flowers, Tolerates wet soil, Wildlife value
- Sold as: Saplings, Seed

Heights and zones are typical ranges for the species in cultivation; local conditions and seed source shift them.

## Availability

Not yet priced online. Ask at captain@bluewhaletrees.com or leave an email on the web page to be told when it is listed.

## Notes

Smooth-bark St. John's-wort grows wild only around the sinkhole ponds and sandhill lakes of Bay and Washington counties in the Florida Panhandle, where it often rings the shore as the main shrub. It is the tree among the St. John's-worts, a narrow evergreen on one trunk with needle-like, gray-green leaves. Its smooth, chestnut-brown bark turns metallic silver and peels in thin, curling sheets like a birch's. Florida lists it as endangered, and NatureServe ranks it imperiled. Plant it at the wet edge of a pond or rain garden, where its silver trunks and yellow flowers show above the water.

## Size, growth and what to expect

No source rates its growth, so our growth estimator uses the middle rate, about a foot and a half a year. It makes a narrow, upright shrub 6 to 10 feet tall and 3 to 5 feet wide, and some reach 13 feet. It grows on a single trunk with a bushy crown. Its needle-like, gray-green leaves run half an inch to an inch long.

Bright yellow flowers half an inch to three quarters of an inch across open from May until frost, each with about 200 stamens. Small capsules follow, each holding many tiny seeds. In the wild a bank of seed in the soil lets stands come back after a drought.

It grows wild only in Bay and Washington counties, Florida, on the rising and falling shores of sinkhole ponds and small lakes set in longleaf pine and scrub oak sandhills. There it may stand in water in wet years and on dry sand in droughts. Clearing lakeshores for beaches is its main threat.

## How to grow Smooth-bark St. John's-wort

Smooth-bark St. John's-wort grows best in full sun and takes light shade. It wants a moist to wet, acid, sandy soil, and it stands periods of flooding. In the wild the water can rise over its roots to 5 feet deep. Once rooted it rides out a dry spell, but the long drought of 1999 to 2003 killed many wild plants, so keep it moist. Set plants 3 feet apart and 3 feet from a wall. At its size it can go within 15 feet of overhead wires.

Saplings ship bare-root or potted. Plant them in a hole wider than the roots and no deeper. Set the crown at the soil line, put the native soil back in, and keep the mulch clear of the stem. Seed is hard to raise. In one trial only 8.5 percent of fresh seed and 21 percent of frozen seed sprouted. Press it onto damp, peaty sand without covering it, since other St. John's-worts need light to sprout.

Water weekly through the first summer unless the ground stays wet. Plants standing in water grow woody prop roots at the base, which is normal. It needs little pruning.

Each flower carries both male and female parts, so there are no male and female plants to pair. Bees work the flowers, and birds and mammals eat the leaves and seeds. Watch for rust, and powdery mildew may turn up.

## Sources

- [Flora of North America, vol. 6: Hypericum lissophloeus (Norman K. B. Robson)](http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250100853)
- [NatureServe Explorer: Hypericum lissophloeus, Smooth-barked St. John's-wort](https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.136635/Hypericum_lissophloeus)
- [Florida Natural Areas Inventory: Smoothbark St. John's Wort field guide, December 2021](https://www.fnai.org/PDFs/FieldGuides/Hypericum_lissophloeus.pdf)
- [Florida Natural Areas Inventory: Tracking List](https://www.fnai.org/PDFs/tracking/element_tracking_summary_current.pdf)
- [Missouri Botanical Garden Plant Finder: Hypericum lissophloeus](https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=364599&isprofile=0)
- [Florida Native Plant Society: Hypericum lissophloeus, smoothbark St. John's-wort](https://www.fnps.org/plant/hypericum-lissophloeus)
- [Historic Columbia, Garden Database: Hypericum lissophloeus](https://www.historiccolumbia.org/garden-search/detail/hypericum-lissophloeus)
- [U.S. Fish and Wildlife Service, ECOS: Smooth barked St. John's wort, Hypericum lissophloeus](https://ecos.fws.gov/ecp/species/5573)
- [USDA NRCS PLANTS Database: Hypericum lissophloeus, HYLI4](https://plants.usda.gov/plant-profile/HYLI4)

## Read before planting

- [Ten planting mistakes that quietly kill trees](https://bluewhaletrees.com/articles/ten-planting-mistakes/index.html.md)
- [Transplanting young trees: timing, water and protection](https://bluewhaletrees.com/articles/transplanting-young-trees/index.html.md)
- [Protecting young trees from voles, rabbits, deer and squirrels](https://bluewhaletrees.com/articles/protecting-trees-from-animals/index.html.md)
- [The habitat around a tree is part of the tree](https://bluewhaletrees.com/articles/habitat-around-a-tree/index.html.md)
- [Invasive vines and shrubs are what is killing your woods](https://bluewhaletrees.com/articles/invasive-vines-and-shrubs/index.html.md)
- [Native trees and shrubs for birds: caterpillars, fruit, mast, nests and winter cover, month by month](https://bluewhaletrees.com/articles/native-trees-for-birds/index.html.md)

## Related

- [Planting-site check](https://bluewhaletrees.com/tools/site-check/index.html.md): for a thrive, struggle or fail verdict on Smooth-bark St. John's-wort, add ?species=smooth-bark-st-johns-wort with zone (2 to 10), sun (full, part, shade) and moisture (dry, average, wet) to that address, for example ?species=smooth-bark-st-johns-wort&zone=7&sun=part&moisture=average.
- [Companion species for Smooth-bark St. John's-wort](https://bluewhaletrees.com/tools/companions/index.html.md?species=smooth-bark-st-johns-wort): the natives that share its ground and the plants that pair with it in a yard.
- [Growth estimator](https://bluewhaletrees.com/tools/growth/index.html.md): how the height and trunk projections are made; the estimate itself runs in the browser at https://bluewhaletrees.com/tools/growth/#species=smooth-bark-st-johns-wort
- [Seed sowing planner](https://bluewhaletrees.com/tools/sowing/index.html.md): how Smooth-bark St. John's-wort is sown, in the chart for every species (treatment, cold days, depth, timing); the dated plan runs in the browser at https://bluewhaletrees.com/tools/sowing/#species=smooth-bark-st-johns-wort
- [Pollination planner](https://bluewhaletrees.com/tools/pollination/index.html.md): what Smooth-bark St. John's-wort needs for a crop and how many to plant, in the table for every species; the planner runs in the browser at https://bluewhaletrees.com/tools/pollination/#plants=smooth-bark-st-johns-wort:1
- [Bloom and fruit calendar](https://bluewhaletrees.com/tools/calendar/index.html.md): the months Smooth-bark St. John's-wort flowers and fruits, in the grid for every species.