Botanist's Lens: Yarrows, St. Johns-wort, & Spurge - Great for Hot Summers

Summer just got hotter!

Yarrow, Achillea millefolium 'Paprika'

Summer went from hot to hotter to hottest in a matter of days. Even for garden beds with automated irrigation, hot-humid weeks can send us in a rush to check on water for lawns, garden beds, delicate annuals and planters.

Like your garden, but not so much the moisture checks? Well, if you get full sun and would like at least one section in your garden that you don’t have to rush to check on water - even on the hottest days - then you might want to add some of following plants: Yarrows, St. John's-wort, and Euphorbias, also known as Spurge.

Yarrow, Achillea millefolium 'Moonshine'


Yarrow, Achillea millefolium, is a rewarding all season bloomer. The feathered aromatic leaves are gorgeous in of itself, and the inflorescence is stunning. Featured today are 'Moonshine' with a yellow brighter than the sun and 'Paprika' that would set the temperatures soaring even on grey cloud cover days.

Yarrows have high ethnobotanical uses. "The genus name Achillea refers to Achilles, hero of the Trojan Wars in Greek mythology, who used the plant medicinally to stop bleeding and to heal the wounds of his soldiers". Source

St. John's-wort, Hypericum 'Hidcote' flower close up (Photo courtesy: Dylan Bacon, Landscape Manager

St. John's wort

St. John’s-wort, Hypericum 'hidcote,' is my go to plant for disturbed soils and full sun/part sun spots. 'Hidcote' is a compact variety for small sections. There are over 400 species in this genera and with its habit of accommodating most disturbed soils, some species do act aggressive. Look for the most compact and less aggressive variety or if you have a wide open space then add the native densiflorum. Source

Euphorbia x martinii 'Ascot Rainbow' with variegated leaves


Euphorbias, commonly called as Spurge, is a large genus. Their distinct features include a white milky latex like sap and unique flowers that are either male or female. Most interestingly: "It is the only genus of plants that has all three kinds of photosynthesis, CAM, C3 and C4." Source

Spurge, Euphorbia

This genus has over 2,000 species! The succulents use the CAM, while Chamaescy sp. use the C4, and the rest use C3. Spurges can add the brightest chartreuse green to any sunny spot making it even brighter.

Euphorbia x martinii 'Ascot Rainbow' flower

Yarrows, Euphorbias and Hypericums are all hardy perennial shrubs. Less maintenance and lower water requirements resonates well with perennials and even more so with natives.

Summer gardens must have at least some maintenance free plants. Greens that love the soaring high temperatures and that don't quench for water until it rains next, are the ones that make sunny summer gardens most enjoyable.

Grow the ReLeaf Fund

Recently, London Town launched the ReLeaf Fund. This newly created fund was inspired by the cycle of renewal in our gardens. Donations to it will ensure that London Town will grow again. Funds will be matched up to $35,000! Learn more and donate today!

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