The Public Herbarium

Bee Balm (Monard fistulosa) flower

Staying Cool, Hydrated, and Protected During the Warmer Months

Summer in New Zealand is a time of outdoor adventures, beach trips, and long evenings in the garden. But the heat, sun exposure, and increased activity bring their own challenges: dehydration, sunburn, heat exhaustion, and the mental stress that comes with overheating. Herbs can help you stay cool from the inside out, protect your skin, and maintain energy without feeling frazzled.

This guide focuses on practical herbal strategies for managing summer’s unique health demands in Aotearoa New Zealand.

Cultural Context and Scope

This guide addresses summer herbal support from a Western herbalism and evidence-based perspective. While the herbs featured (peppermint, hibiscus, lemon balm, calendula, cucumber) are not native to Aotearoa New Zealand and are not taonga species in rongoā Māori, it remains important to acknowledge:

Rongoā Māori and Seasonal Healing:
Rongoā Māori has its own seasonal practices and frameworks for managing heat, hydration, and summer health challenges, passed down through generations. These practices encompass physical, spiritual, and communal dimensions.

This Guide Focuses On:
Western herbal strategies using commonly available herbs for cooling, hydration, skin protection, and stress management during New Zealand’s summer months.

Why Summer Herbal Support Matters

Prevention over Crisis:
Starting cooling herbs early in summer — before heat stress occurs — is more effective than waiting until you’re overheated, dehydrated, or sunburned.

Gentle Daily Support:
Unlike harsh cooling methods, herbs provide gentle, sustained support that works with your body’s natural thermoregulation and skin repair mechanisms.

Accessibility:
Many summer herbs are inexpensive or free — mint grows prolifically in gardens, cucumber is a staple vegetable, lemon balm self-seeds everywhere. Even dried hibiscus costs only $12-18/50g and makes litres of cooling tea.

Connection to Season:
Making iced herbal teas, harvesting calendula flowers, and applying after-sun remedies creates mindful engagement with summer rather than just enduring the heat.

Cost Savings:
Commercial after-sun products cost $15-30, but homemade calendula salve costs $5-8. A $5 mint plant provides fresh cooling tea all summer instead of buying commercial beverages at $4-6 each.

Understanding Summer Health Challenges

Heat Stress and Thermoregulation

Your body works hard to maintain its core temperature around 37°C. When environmental temperature rises, your body cools itself primarily through:

Sweating: Your most important cooling mechanism. As sweat evaporates from your skin, it removes heat from your body.

Vasodilation: Blood vessels near your skin surface expand, allowing more blood flow to release heat.

Breathing: Some heat is released through exhalation, though this is a minor contributor.

Why this matters: When you can’t cool effectively (high humidity prevents sweat evaporation, insufficient hydration limits sweat production, or extreme heat overwhelms your system), you risk heat exhaustion or heat stroke.

Symptoms of heat stress:

Regional Summer Variations in Aotearoa New Zealand

Summer heat challenges vary significantly across New Zealand’s regions:

Northern NZ (Auckland, Northland, Bay of Plenty):

Central NZ (Wellington, Taranaki):

Southern NZ (Canterbury, Otago, Southland):

Coastal vs. Inland:

Adapt your herbal approach to your region. Auckland needs aggressive cooling and anti-humidity support; Otago needs hydration in dry heat and strong sun protection despite cooler temperatures.

Dehydration and Electrolyte Imbalance

Sweating doesn’t just remove water — it also removes electrolytes (sodium, potassium, magnesium, calcium). These minerals are essential for:

Plain water alone isn’t always sufficient for replacing what you lose through heavy sweating.

Sun Exposure and Skin Damage

UV radiation from the sun causes:

Why herbs matter: While herbs should never replace sun protection (shade, clothing, sunscreen), they can support skin resilience, provide after-sun care, and help repair damage.

Key Summer Herbs for New Zealand

Peppermint (Mentha × piperita)

Peppermint (Mentha × piperita) leaves
Peppermint (Mentha × piperita)

Why it’s valuable: Peppermint is perhaps the quintessential summer cooling herb, and it works through an interesting mechanism.

How it works: Menthol (the primary compound in peppermint) activates cold-sensing receptors (TRPM8) in your skin and mucous membranes. This creates a sensation of coolness even without actually lowering body temperature. However, when consumed as a hot tea, peppermint also acts as a mild diaphoretic — it encourages sweating, which then cools you through evaporation.

Uses:

How to use:

Safety: Very safe for most people. Avoid giving peppermint essential oil to infants (can cause breathing difficulties). People with GERD may find strong peppermint worsens reflux.

NZ availability:

Budget Alternative: Any Fresh Mint

Can’t find peppermint specifically? Any mint variety (spearmint, apple mint, chocolate mint) provides cooling effects:

Hibiscus (Hibiscus sabdariffa)

botanical drawing of HIbiscus (Hibiscus sabdariffa)
HIbiscus (Hibiscus sabdariffa)

Why it’s valuable: Hibiscus is cooling, antioxidant-rich, and deeply hydrating. The tart, cranberry-like flavour makes it delicious as an iced beverage.

How it works: Hibiscus contains anthocyanins and other flavonoids that provide powerful antioxidant protection. When you’re spending time in the sun, oxidative stress increases in your skin cells. Antioxidants help neutralise free radicals, reducing damage. Hibiscus also has mild diuretic properties, helping your body release excess heat through fluid elimination.

Uses:

How to use:

Safety: Very safe. Pregnant women should use moderate amounts only (traditionally used to bring on menstruation in high doses).

NZ availability:

Can’t Access Hibiscus?

Alternatives:

Lemon Balm (Melissa officinalis)

Lemon Balm (Melissa officinalis) leaves
Lemon Balm (Melissa officinalis)

Why it’s valuable: Summer isn’t just physically hot — it can be mentally and emotionally overheating too. Overstimulation, disrupted routines, and heat can fray nerves. Lemon balm is both cooling and calming.

How it works: Lemon balm contains rosmarinic acid (anti-inflammatory, antioxidant) and volatile oils that have gentle anxiolytic (anti-anxiety) effects. It modulates GABA receptors in the brain, promoting relaxation without sedation. It’s classified as a “cooling nervine — “it calms the nervous system while having a cooling energetic quality.

Uses:

How to use:

Safety: Very safe, suitable for children. No significant contraindications.

NZ availability:

Calendula (Calendula officinalis)

Calendula (Calendula officinalis) flower
Calendula (Calendula officinalis)

Why it’s valuable: Summer means more time outdoors, which means more scrapes, insect bites, and sun exposure. Calendula is your go-to topical herb for skin issues.

How it works: Calendula contains triterpene saponins and flavonoids with potent anti-inflammatory and wound-healing properties. When applied to skin, these compounds:

Uses:

How to use:

Safety: Very safe topically for most people. Those allergic to Asteraceae family (ragweed, daisies) should patch test first. Not for internal use during pregnancy.

NZ availability:

Cucumber (Cucumis sativus)

Cucumber (Cucumis sativus) fruit
Cucumber (Cucumis sativus)

Why it’s valuable: While not traditionally thought of as an “herb,” cucumber deserves mention as a summer ally. It’s 95% water, cooling, and hydrating.

How it works: Cucumber contains silica, vitamin C, and caffeic acid — all beneficial for skin. The high water content makes it intensely hydrating. The cooling effect is both from the water content and from ascorbic acid (vitamin C), which has mild anti-inflammatory properties.

Uses:

How to use:

Safety: Completely safe for almost everyone.

NZ availability: All supermarkets year-round, $2-5 per cucumber. Grow your own in summer (easy from seed).

Simple Summer Preparations

Cooling Herbal Iced Tea Blend

A refreshing daily beverage to support hydration and cooling.

Ingredients:

Instructions:

  1. Mix dried herbs and store in airtight container
  2. For sun tea: Use 3-4 tablespoons per quart of water, place in sun 4-6 hours, strain, refrigerate
  3. For quick tea: Use 2 teaspoons per cup boiling water, steep 10 minutes, cool, serve over ice
  4. Sweeten with honey if desired, add fresh lemon or lime

Cost: Approximately $25-35 for enough blend to make 20-30 servings.

Why it works: Hibiscus provides antioxidants and minerals, peppermint offers cooling sensation and digestive support, lemon balm calms summer stress. All three are safe, pleasant-tasting, and effective.

After-Sun Soothing Spray

For mild sunburn and heat-stressed skin.

Ingredients:

Instructions:

  1. Combine cooled calendula tea with aloe vera gel in spray bottle
  2. Shake well before each use (aloe doesn’t fully dissolve, needs mixing)
  3. Store in refrigerator (cold application feels better on hot skin)
  4. Spray liberally on affected skin 3-4 times daily
  5. Use within 1 week (no preservatives)

When to use: After sun exposure, on mild sunburn (stage 1 — red skin, no blistering), on heat rash, as a cooling body spray on hot days.

Cost: Under $10 for materials, makes enough for several days of use.

Important: This is for AFTER sun exposure and MILD sunburn. Severe sunburn (blistering, extreme pain, fever) requires medical attention. Never skip sunscreen prevention.

Electrolyte Herbal Drink

Plain water isn’t always enough when you’re sweating heavily. This natural electrolyte drink supports hydration.

Ingredients:

Instructions:

  1. Brew nettle tea: Pour boiling water over nettle, steep 20 minutes covered, strain
  2. Allow to cool
  3. Add sea salt, lemon juice, sweetener
  4. Stir well, refrigerate
  5. Drink throughout day, especially during or after exercise, gardening, or extended time outdoors

Why it works: Nettle provides a full spectrum of minerals, salt replaces sodium lost in sweat, lemon/lime adds potassium and vitamin C, sweetener helps electrolytes absorb into cells.

Cost: $2-3 per batch.

Summer Lifestyle Support

Stay Ahead of Dehydration

Hydration tips:

How much: General guideline is 2-3 litres daily, more if exercising or working outdoors. Individual needs vary.

Sun Protection Basics

Herbs support skin health but do NOT replace sun safety:

When you do get sun exposure: Use after-sun herbs (calendula, aloe) to support skin repair.

Recognise Heat Exhaustion

Symptoms:

Immediate action:

  1. Move to cool, shaded area
  2. Loosen clothing
  3. Drink cool water (small sips if nauseous)
  4. Apply cool, wet cloths to skin
  5. If symptoms don’t improve within 30 minutes, seek medical help

Heat stroke (medical emergency):

Growing Summer Herbs in NZ

Easy summer herbs for beginners:

Peppermint:

Lemon Balm:

Calendula:

Cucumber:

Budget-Friendly Summer Support

If money is very tight, prioritise:

  1. Water: Free from tap
  2. Mint (grow from cutting): Free from friends
  3. Cucumber: $2-4, 95% water
  4. Calendula (grow from seed): $3-5, all summer
  5. DIY electrolyte: Water + salt + lemon = $0.50/L

Free options:

Basic toolkit under $10 provides effective summer support.

Container Growing (Balcony/No Garden)

Peppermint: 20cm+ pot, regular soil, part shade to sun, keep moist. Container essential (spreads). Cost: $15-25 initial.

Lemon Balm: 25cm+ pot, regular soil, part shade to sun, moderate water. Cost: $15-25, self-seeds.

Calendula: 20cm+ pot, full sun, moderate water. Cost: $3-5 seeds, blooms all summer.

Cucumber: 30cm+ pot, rich soil, full sun, consistent water, trellis. Cost: $3-5 seeds, 3-10 cucumbers.

Even small balconies can provide fresh summer herbs.

Where to Source Summer Herbs in NZ

Fresh herbs:

Dried herbs:

Typical prices:

Budget tip: Growing your own reduces costs dramatically. A $5 plant provides fresh herbs all summer, and many (mint, lemon balm, calendula) return year after year or self-seed.

When to Seek Professional Help

See a healthcare provider if:

Herbs are supportive, not replacements for appropriate medical care.

Summary: Your Summer Herbal Toolkit

For cooling and hydration:

For skin protection and after-sun care:

For summer stress and sleep:

Key practices:

Summer in Aotearoa is a gift. With these herbal allies, you can enjoy it fully while protecting your body and staying comfortable even in the heat.

References

Healthline. (2021). Herbal remedies to help you beat the heat. Retrieved from https://www.healthline.com/health/cooling-herbs-to-help-you-beat-the-heat

Mother Earth News. (2025). 5 herbs to beat the heat + 4 summer herbal recipes. Retrieved from https://www.motherearthnews.com/natural-health/5-herbs-to-beat-the-heat-zm0z20aszbut/

Herbal Academy. (2022). DIY frozen aloe and calendula cubes to soothe sunburns. Retrieved from https://theherbalacademy.com/blog/soothe-sunburns/

McKay, D. L., & Blumberg, J. B. (2006). A review of the bioactivity and potential health benefits of peppermint tea (Mentha piperita L.). Phytotherapy Research, 20(8), 619-633.

Hopkins, A. L., Lamm, M. G., Funk, J. L., & Ritenbaugh, C. (2013). Hibiscus sabdariffa L. in the treatment of hypertension and hyperlipidemia: A comprehensive review of animal and human studies. Fitoterapia, 85, 84-94.

Kennedy, D. O., Little, W., & Scholey, A. B. (2004). Attenuation of laboratory-induced stress in humans after acute administration of Melissa officinalis (lemon balm). Psychosomatic Medicine, 66(4), 607-613.

Preethi, K. C., & Kuttan, R. (2009). Wound healing activity of flower extract of Calendula officinalis. Journal of Basic and Clinical Pharmacy, 1(1), 68-72.

Disclaimer: This guide is for educational purposes only and is not medical advice. It does not represent rongoā Māori seasonal health practices. For rongoā Māori perspectives on summer wellness, consult qualified rongoā practitioners through Te Paepae Motuhake, local marae, or Māori health providers. Always consult qualified healthcare practitioners before using herbal remedies, especially if pregnant, nursing, taking medications, or having medical conditions. Heat stroke is a medical emergency — call 111 if symptoms are severe. Herbs do not replace appropriate sun protection measures.

Note on Pricing: All prices mentioned in this guide are approximate and based on New Zealand suppliers as of December 2025. Prices vary by supplier, season, and market conditions. We recommend checking current prices with your local suppliers.

The Public Herbarium is built on a foundation of scientific integrity, transparency, and care. Research sources are referenced throughout the site wherever possible. Content creation is assisted by AI tools and carefully reviewed for accuracy.