Moringa peregrina

Plant Profile & Key Characteristics

Overview: A desert shrub or tree reaching 5-10 m, evergreen or drought/cold-deciduous, grown for its edible leaves, pods and seeds. It is very drought-tolerant and suits arid gardens.

Quick Specifications

Specification	Attribute
Plant Type / Life Cycle	Perennial (shrub or tree)
Foliage Type	Evergreen or deciduous (summer-deciduous in heat, winter-deciduous in cold)
Mature Size	5-10 m (15-30 ft)
Growth Rate	Slow to Fast (variable)
Root System	Deep taproot
Toxicity	Leaves, pods and seeds edible
Hardiness	USDA zone 10+

Growth Form & Structure

• Height & Spread: 5-10 m (15-30 ft); can be container-grown.
• Growth Habit & Form: Sparse desert shrub or tree; branches can be brittle and occasionally fall.
• Lifespan & Maturity: Bears pods in about 1.5-3 years.

Anatomy & Physical Features

• Leaves & Foliage: Light-to-dark green odd-pinnate leaves with elliptic leaflets; edible.
• Flower Characteristics: White-pink flowers that attract pollinators.
• Fruit Profile: Green edible pods, fully edible when young and with an edible inner part when ripe.

Primary Uses & Landscape Value

• Edible Uses: Leaves eaten in salad or cooked; edible young pods and seeds.
• Functional & Ornamental Roles: Drought-hardy food tree; ornamental in arid gardens.

Care Guide: Planting, Soil & Watering

Overview: Moringa peregrina is a drought-hardy desert shrub or tree for full sun to part shade in warm, essentially frost-free climates (hardiness zone 10+). It thrives in light, sharply drained soil with little water.

Quick Care Requirements

Requirement	Ideal Condition
Planting Season	Spring in cooler areas; autumn in the desert
Growth Rate	Slow to Fast, depending on conditions
Soil Type	Light, sharply draining; tolerates poor, sandy ground
Water Need	Low to Moderate – very drought-tolerant once established

Planting & Establishment

• Best Planting Season: Plant in spring in cooler areas, or in autumn in hot desert climates, so young plants avoid frost.
• How to Plant:
  • Hole Preparation: Dig a hole about twice the width of the root ball in a warm, sunny, well-drained position.
  • Soil Amendments: Keep the soil light and free-draining, adding only a little compost to very poor ground.
  • Planting Depth: Set the root collar at soil level; do not bury the stem.
• Growth Speed & Expectations: Variable – from slow to fast depending on warmth and water, generally steady in its harsh native conditions.

Soil, Watering & Drainage Care

• Soil Mix & Drainage Needs: Needs very sharp drainage; sandy desert soils suit it, and wet, heavy ground will rot the roots.
• Watering Schedule & Technique:
  • Young / Newly Planted: Water young plants occasionally to establish them, letting the soil dry well between waterings.
  • Established: Extremely drought-tolerant once established; water deeply but rarely.
  • Seasonal Adjustments: Water a little more in extreme heat; keep nearly dry in winter and cool weather.

Climate, Light & Hardiness

Moringa peregrina (Moringa peregrina) is a desert-adapted shrub or tree of arid subtropical, tropical, Mediterranean and desert regions that needs full sun and intense heat. Grown in roughly USDA zone 10 and warmer, it is frost-tender - frost kills soft top growth - though established plants tolerate a small amount of brief frost.

Quick Climate Specifications

Climate Zones	Desert, subtropical, tropical, Mediterranean
USDA Hardiness Zones	Approximately 10 and warmer
Optimal Temp Range	Hot, roughly 25–38 °C (77–100 °F)
Cold Damage Begins	At light frost; soft growth is killed first
Approx. Survival Minimum	Established plants take brief light frost near freezing, roughly −1 to 0 °C (30 to 32 °F); harder freezes kill top growth
Frost Tolerance	Very low
Light Conditions	Full sun
Wind Tolerance	Moderate

Sunlight & Light Exposure

Optimal Light Setup

Full, direct sun is essential; this is a plant of open, sun-baked desert sites and will not thrive in shade.

Direct Sun Requirement

High - strong sun and heat drive its growth.

Best Exposure / Orientation

The hottest, sunniest position available is ideal, with shelter helping at the cool edge of its range.

Temperature Extremes & Hardiness

USDA Hardiness & Regional Limits

Suited to roughly zone 10 and warmer - a little more cold-cautious than Moringa oleifera. Young plants are more cold-sensitive than established ones, and tolerance varies with age, exposure duration and conditions.

Cold Damage & Winter Protection

Light frost damages soft growth; established plants may take a brief, light freeze and recover. A warm, sheltered site and root-zone mulch aid recovery in marginal areas.

Frost Sensitivity

Frost-tender above ground; it is deciduous in response to season, dropping leaves in cold or in hot-dry stress.

Extreme Heat Tolerance

Exceptional - a true desert species thoroughly at home in extreme heat.

Wind, Humidity & Microclimate

Dry-Air Tolerance

Superb tolerance of very dry, hot air - one of its defining desert traits.

Wind Tolerance

Moderate; some shelter protects young, sappy growth in exposed desert wind.

Microclimate Recommendations

A hot, open, sheltered position gives the best growth and the best resilience to an occasional cold night.

Growing in Pots, Balconies & Indoors

Moringa peregrina is a desert moringa (5-10 m) adapted to hot, dry conditions. It is not a houseplant, as the grower confirms, but it grows in a large, very free-draining container on a hot, sunny patio, and potting lets you shelter it from frost.

Quick Details

• Container Size: A large, deep tub for its taproot; keep it pruned to a manageable size
• Indoor Suitability: Not a houseplant (per the grower) – a sun-loving desert tree
• Best Spot: Full sun to half shade
• Soil & Drainage: Sharp, gritty, very free-draining mix – it must never stay wet
• Watering in Pots: Small; let it dry out well between waterings – it’s very drought-adapted

Indoors & On the Windowsill

• Houseplant limits: The grower marks it no for indoors; it’s a desert tree that needs intense outdoor sun.
• Overwintering indoors: Frost-tender – in cold climates keep it potted and move it into a warm, bright, dry, frost-free space over winter, watering very sparingly.

On a Balcony or Patio

• Light & wind: Give it the hottest, sunniest spot and sharp drainage; it thrives on heat and tolerates drought, so err on the dry side. Mind the weight of a large tub.

Choosing the Pot, Soil & Long-Term Care

• Pot & drainage: Use a pot with strong drainage holes and skip a standing-water saucer, which invites root rot; terracotta breathes and dries faster, while glazed or plastic holds moisture longer.
• Potting mix: A light, aerated organic mix – a gritty, very free-draining mix – loam or coir with plenty of grit and perlite – gives the roots both moisture and air.
• Feeding: Potted plants use up their feed faster because each watering leaches nutrients away, so feed a little more often than plants in open ground.
• Repotting: Refresh the top of the mix and pot up every couple of years; a light root and top prune at repotting keeps established plants vigorous.

Fertilizing & Feeding

A moderate feeder: drought-hardy Moringa peregrina needs only light, balanced feeding through the active season, with a little extra nitrogen while young to support leafy growth.

Quick Fertilizing Specs

Feeding Level	Moderate
young_feeding	Nitrogen-leaning complete fertilizer to build the framework
mature_feeding	Balanced feeding with adequate potassium as it bears
Main Nutrient Priority	Nitrogen when young; balanced with adequate potassium as it bears
Best Feeding Period	From late dormancy through the active growing season
Organic Options	Compost, aged manure and mulch
Micronutrients	Usually supplied by a complete fruit-tree fertilizer; iron may need attention on alkaline soils
Soil pH	Tolerates a wide range; needs well-drained soil
Reduce/Stop Feeding	Ease back in late season and during dormancy

Feeding by Growth Stage

Newly planted

Help the newly planted Moringa peregrina settle in and push healthy roots and first shoots.

Nutrient direction	A gentle, balanced complete fertilizer once new growth appears, kept light while roots establish.
Timing	The first growing season after planting, once the tree shows active new growth.
Frequency	Light feeding spread across the active growing season.
Fertilizer types	Balanced complete garden or fruit-tree fertilizer, Compost or well-rotted organic matter worked into the surface
Precautions	Keep fertilizer off the trunk and avoid heavy applications before roots establish.

Young, pre-bearing tree

Build a strong framework of shoots and foliage on the young, non-bearing Moringa peregrina.

Nutrient direction	Lean a little more toward nitrogen to drive vegetative growth, supplied within a complete fertilizer.
Timing	Through the active growing seasons of the young, pre-bearing years.
Frequency	Several light feedings across the growing season.
Fertilizer types	Nitrogen-forward complete fruit-tree fertilizer, Compost and mulch for steady background nutrition
Routine trace nutrients	iron, manganese, zinc
Precautions	Avoid pushing soft, late-season growth with excess nitrogen, as it is prone to cold and pests.

Established, beginning to bear

Support steady growth and the first crops as Moringa peregrina begins to bear.

Nutrient direction	Return to a balanced complete fertilizer that supplies nitrogen with adequate potassium.
Timing	From late dormancy into the active growing season as bearing begins.
Frequency	A few light feedings during the active growing season.
Fertilizer types	Balanced complete fruit-tree fertilizer, Compost or aged manure as organic backing
Routine trace nutrients	iron, manganese, zinc
Precautions	Feed to match the tree’s growth rather than a fixed schedule.

Mature and bearing

Sustain reliable cropping and fruit quality on the mature, bearing Moringa peregrina.

Nutrient direction	Keep a balanced base with enough potassium as fruit develops, while avoiding excess nitrogen that favours leaves over fruit.
Timing	From late dormancy through fruit development in the active growing season.
Frequency	Light feedings early in the season, easing back as fruit ripens.
Fertilizer types	Balanced fruit-tree fertilizer with adequate potassium, Compost and mulch to maintain soil organic matter
Routine trace nutrients	iron, manganese, zinc
Precautions	Excess nitrogen can reduce fruiting and attract pests, so feed to match growth rather than a fixed schedule.

Nutrient Deficiency Signs & Corrections

Older leaves turn pale green to yellow and shoot growth slows.

Possible causes	Low soil nitrogen, Cold or waterlogged soil limiting uptake, Heavy grass or weed competition around the trunk
Appears first on	Older, lower leaves
What to check	Recent feeding history, Soil drainage and root health, Weed competition at the base
Possible correction	Apply a complete nitrogen-containing fertilizer as growth resumes and build soil organic matter with compost.

Youngest leaves yellow between still-green veins.

Possible causes	High soil pH reducing iron availability, Waterlogged or cold soils, A genuine iron shortage
Appears first on	Youngest leaves at the shoot tips
What to check	Soil pH, Drainage, Whether only new growth is affected
Possible correction	Correct soil pH where possible and apply a chelated iron product per its label.

Margins of older leaves scorch and brown and fruit quality drops.

Possible causes	Low soil potassium, Heavy fruit load drawing down reserves, Sandy soils that leach potassium
Appears first on	Margins of older leaves
What to check	Soil potassium status, Fruit load, Soil type and leaching
Possible correction	Feed with a potassium-containing complete fertilizer during fruit development.

Pruning, Training & Seasonal Maintenance

Moringa peregrina tolerates moderate to fairly assertive pruning, and unlike most trees the trigger for cutting is often mechanical weakness rather than shape: its branches are notably brittle and can break or drop on their own, so removing weak, poorly attached or already-damaged wood is the main ongoing job. Because the tree grows in a frost-free climate but is only marginally frost-tolerant, pruning can be carried out year-round with no strict seasonal window, though heavy cuts are best avoided right before a cold spell. Many growers also keep it deliberately compact and multi-branched while young, since a smaller, wider canopy keeps the edible young leaves within easy reach.

Quick Pruning & Maintenance Specs

Pruning Tolerance	Moderate-High
Primary Pruning Window	Year-round (frost-free climate)
Typical Frequency	Inspect periodically; remove weak or dead wood as it appears
Main Objective	Remove weak/brittle branches before they fail; keep the canopy accessible
Young Plant Priority	Select well-attached scaffold branches; shape to a low, multi-branched small tree if easy leaf access is wanted
Mature Plant Priority	Ongoing removal of weak, dead or storm-prone limbs; height control
Best Tool Type	Bypass secateurs and loppers for small wood; saw for larger weak limbs
Avoid Heavy Pruning During	Cold snaps (only marginally frost-tolerant)

Pruning by Plant Age & Size

Newly Established

Limit cuts to damaged or transplant-stressed growth; avoid heading back a young plant unless deliberately building a multi-branched, low-canopy form.

Young / Formative

Choose the framework early: a few well-spaced, wide-angled scaffold branches. Because the wood is brittle, narrow, included-bark crotches are a long-term liability and are best removed or corrected while branches are still small rather than left to fail later.

Mature / Established

Routine removal of weak, cracked or dead branches (the species is prone to shedding limbs); height and spread control if the tree is being kept smaller than its natural 5-10 m (15-30 ft).

Structural Pruning & Training

Prioritise removing crossing, rubbing or narrow-angled branches early – this matters more here than on most trees because weak wood makes a poorly attached limb a real breakage risk rather than just a cosmetic issue. Height/spread reduction is reasonable where a smaller, easier-to-reach canopy is preferred.

Special Growth to Remove

Dead wood and structurally weak branches (splitting, cracked, or narrow-crotched) are the priority removals for this species, ahead of the cosmetic suckering/watersprout concerns typical of grafted fruit trees.

Container & Small-Space Pruning

Grows readily in a container. Regular pruning is the main tool for keeping a containerized specimen well within reach and structurally sound, since restricted roots do not reliably slow the brittle top growth on their own.

Tools

Bypass secateurs for thin, weak shoots; loppers for small-to-medium branches; a pruning saw for larger weak or already-cracked limbs. A pole pruner is only needed on specimens allowed to reach their full 5-10 m height.

Tool Hygiene & Disease Risk

Routine – clean, sharp tools are sufficient; no transmissible disease risk is noted for this species (its main pest is caterpillar feeding, not a cut-borne pathogen).

Cut Placement & Technique

Cut just outside the branch collar and avoid flush cuts. On larger weak or already-splitting limbs, remove in stages (undercut first) to prevent the brittle wood from tearing bark down the trunk as it falls.

Heavy Pruning & Rejuvenation

The species’ fast-to-medium growth rate and brittle wood mean it recovers size fairly readily after a significant cutback, but there is no strong evidence for treating this as routine coppicing – reduce size gradually over more than one session rather than removing most of the canopy at once, and expect a temporary drop in leaf/pod production while it regrows.

Post-Pruning Care

Watch cut sites on this brittle-wooded species for dieback or secondary cracking; keep watering consistent while new growth resumes. Do not follow pruning with extra feeding.

Common Pruning Mistakes

Leaving narrow-angled or weak branches in place until they tear out on their own instead of removing them while small; flush-cutting or leaving stubs on a species already prone to breakage; letting the tree grow to full height when the whole point of keeping it was easy leaf access.

When NOT to Prune

Avoid heavy pruning immediately before or during a cold snap, since this species is frost-free-adapted and only survives small amounts of frost – fresh cuts and forced new growth are more cold-sensitive.

Recommended Tools (by task)

• Bypass secateurs – removing thin weak shoots and dead twigs on young or small specimens.
• Loppers – small-to-medium weak or dead branches out of secateur range.
• Pruning saw – larger weak, cracked or dead limbs on mature trees.
• Pole pruner – upper weak/dead wood on specimens left to grow to their full 5-10 m height.

Pruning Troubleshooting

Problem	Possible Cause	What to Check	Corrective Action
Branches breaking or dropping unexpectedly	Naturally brittle wood, often worsened by narrow crotch angles	Crotch angle, included bark, any existing cracks	Remove weak-angled or cracked branches proactively rather than waiting for failure
Canopy too tall for easy leaf harvest	Left to grow unchecked while young	Height vs. reach from the ground	Formative height control while the tree is still small

Propagation Guide

Moringa peregrina is grown mainly from seed, but unlike its relative M. oleifera its seed germinates more slowly and erratically, so soaking or light scarification of the seed coat helps. Vegetative propagation is possible but less reliable. Overall moderate.

Quick Propagation Specs

Best Propagation Method	Seed (soaked / lightly scarified)
Alternative Methods	Hardwood cuttings (less reliable than in M. oleifera)
Propagation Difficulty	Moderate
Seed True-to-Type	Reasonably uniform
Vegetative True-to-Type	Yes
Best Propagation Season	Spring in cooler areas; autumn in the desert; warm season generally

Growing from Seed

Seed Handling & Viability

This desert species has a firmer seed coat than M. oleifera; soaking, or nicking the coat, improves otherwise slow and uneven germination.

Sowing Season

Spring in cooler areas, autumn in the desert, matching the site’s planting seasons.

Sowing Depth & Orientation

Sow about 1–2 cm deep, direct or in deep containers to suit the taproot.

Germination Conditions

Warm, free-draining medium; germination may be slow and staggered.

Stem Cuttings

Hardwood cuttings can be tried in the warm season but strike less readily than in M. oleifera, so seed remains the more dependable route.

Bloom & Flower Guide

Quick Details

• Bloom Season: Spring to summer
• Time to First Bloom: Usually within the first few years as the tree establishes
• Flower Appearance: Delicate pink-to-cream flowers
• Edibility: Grown ornamentally and valued as a nectar (honey) plant; not treated here as a culinary flower

Detailed Blooming Overview

A desert-adapted moringa, this species carries soft pink-and-cream flowers that stand out against its sparse, fine foliage. The blooms are an important nectar source in dry country, drawing bees and other pollinators when little else is in flower.

Flower Characteristics

• Pink-to-cream flowers, borne in loose sprays.

Bloom Care & Thinning

• Managing the bloom: Little intervention is needed; light pruning after flowering keeps the form open.
• Pollination: Bees are the main visitors, and the flowers attract pollinators well.

Fruit & Uses

This desert moringa is grown as a food plant for its edible leaves, young pods and seeds. The leaves are used as a green and the young pods and seeds are eaten, with the seeds also valued regionally for their oil.

Quick Edible Specs

Edible Parts	Leaves; young pods; seeds
Main Use(s)	Culinary – leaves as a green (salad or cooked), young pods cooked, seeds eaten (and traditionally pressed for oil)
Eaten Raw or Cooked	Leaves and seeds raw or cooked; pods cooked
Preparation Required	Ripe pods use only the inner part; seeds need the white seed-coat removed
Harvest Season	Leaves all year; pods summer to autumn (all year in the tropics)
Storage	Leaves used fresh or dried
Safety/Toxicity Caveat	No specific toxic part noted in the site data; use ripe pods for the inner pulp and seeds rather than the fibrous wall

Leaves & Greens

The light-to-dark-green pinnate leaves can be picked all year once the plant is established, with no special technique needed. They are eaten raw in salads or cooked. Keeping the tree small by pruning makes leaf picking easier.

Seeds, Pods & Nuts

The green pods are eaten while young and tender; once fully ripe only the inner part is used because the outer wall becomes fibrous. The seeds are edible after the white seed-coat is peeled off and have a sweet-bitter taste, eaten raw or cooked. Regionally the seeds are also pressed for their oil. Pick pods young for whole use, or leave them to mature if you want the seeds.

Preparation, Uses & Safety

Leaves and seeds may be eaten raw or cooked, while pods are cooked. No specific toxic part is recorded for this species in the site data; simply use young pods whole and shell ripe pods for the inner pulp and seeds, removing the white coat from the seeds first.

Pests, Diseases & Troubleshooting

Overview: Moringa are fast-growing, generally resilient trees, but their soft young foliage and pods attract aphids, caterpillars and specific budworms and fruit flies, while the roots and stems can rot in waterlogged or cold soil. The tree’s vigor lets it outgrow most damage; sanitation, pruning and encouraging beneficials handle the rest.

Quick Troubleshooting Overview

Issue / Pest	Main Symptom	Primary Solution
Aphids (with ants)	Curled shoot tips, honeydew, ant activity	Rinse, control ants, insecticidal soap
Budworm / leaf webworm	Webbed, eaten buds and leaves, defoliation	Remove webs, Bt or spinosad, sanitation
Fruit fly	Maggoty, distorted pods	Bag pods, traps, remove infested pods
Caterpillars	Chewed, skeletonized foliage	Hand-pick, Bt, encourage predators
Root rot / damping-off	Wilting, blackened base, seedling collapse	Improve drainage, ease watering
Wind / frost damage	Snapped brittle branches, frost dieback	Shelter, prune, protect from cold

Common Pests & Management

• Aphids (Aphis / Toxoptera spp.):
  • Symptoms: Dense colonies on soft new shoots, flower stalks and leaflets, causing curling, stunting, honeydew and sooty mold; ants farm and protect them, which is why ants appear alongside.
  • Prevention & Control: Wash off with water, control the ants with barriers or bait to expose the aphids to predators, and encourage ladybugs and lacewings. Insecticidal soap or neem clears heavy colonies; avoid excess nitrogen.
• Moringa budworm / leaf webworm (Noorda moringae / Noorda blitealis):
  • Symptoms: Caterpillars web together and bore into flower buds (budworm) or web and eat leaves (leaf webworm), causing bud drop, webbed skeletonized foliage and defoliation.
  • Prevention & Control: Prune out and destroy webbed buds and shoots, keep the area clean, and encourage parasitic wasps. Bt (Bacillus thuringiensis) or spinosad in the evening controls larvae; act early before webbing protects them.
• Fruit fly (Gitona / Bactrocera spp.):
  • Symptoms: Flies lay in developing pods, whose seeds and walls are then tunneled by maggots, leaving distorted, oozing or dropped pods.
  • Prevention & Control: Bag pods for seed, hang protein-bait or pheromone traps, and collect and destroy infested and fallen pods; harvest young pods promptly for eating.
• Caterpillars / hairy caterpillars (Spodoptera / Eupterote spp.):
  • Symptoms: Leaf-eating caterpillars chew and skeletonize foliage, sometimes defoliating young trees in outbreaks.
  • Prevention & Control: Hand-pick where practical, remove egg masses, and encourage birds and predators; Bt or spinosad handles larvae on smaller trees.
• Termites and borers (Odontotermes / stem borers):
  • Symptoms: Termites attack roots and stems of stressed or young trees; borers tunnel stems, causing wilting and dieback.
  • Prevention & Control: Keep trees vigorous and unstressed, remove dead wood, avoid piling mulch against the trunk, and treat active termite nests around the root zone as needed.

Diseases & Fungal Issues

• Root rot and damping-off (Pythium / Rhizoctonia / Diplodia):
  • Symptoms: Seedlings collapse at the soil line (damping-off), and older trees wilt with a blackened, soft base and rotted roots in wet, poorly drained or cold soil.
  • Treatment & Management: Sow in free-draining media, avoid overwatering, and never leave the tree waterlogged. Improve drainage, remove affected plants, and treat seed or drench with a biological or copper product for damping-off.
• Twig and stem canker / dieback (Diplodia / Fusarium spp.):
  • Symptoms: Sunken cankers, oozing and progressive dieback of twigs and branches, often entering through wounds or on stressed trees.
  • Treatment & Management: Prune out cankered wood well below the lesion with sterile tools, avoid mechanical injury, and keep the tree vigorous; paint or protect large cuts.
• Powdery mildew / leaf spot (Leveillula / Cercospora spp.):
  • Symptoms: White powdery patches or brown leaf spots in humid, crowded conditions, causing leaf yellowing and drop.
  • Treatment & Management: Prune for airflow, remove affected leaves, and avoid overhead evening watering; sulfur or copper fungicide helps if it spreads.
• Fruit rot (Cochliobolus / Colletotrichum spp.):
  • Symptoms: Soft, discolored rotting of pods in wet weather.
  • Treatment & Management: Improve airflow, remove affected pods, harvest promptly, and avoid overhead watering.

Growing Difficulties & Abiotic Problems

• Waterlogging and root death:
  • Cause & Symptoms: Moringa is very intolerant of wet feet; standing water quickly kills roots and the tree.
  • Correction Strategy: Plant in free-draining or sandy soil, never overwater, and site on a mound in heavy ground.
• Frost and cold damage:
  • Cause & Symptoms: As a tropical/subtropical tree it defoliates or dies back in frost and stops growing in cold.
  • Correction Strategy: Protect young trees, grow in the warmest spot or as a cut-back plant in cold climates, and expect recovery from the base after light frost.
• Wind and self-breakage:
  • Cause & Symptoms: The brittle, fast-grown wood snaps in wind and under heavy pod loads.
  • Correction Strategy: Shelter from strong wind, prune to a strong framework and keep trees headed low, and stake young trees.

What Helps — Products & Tools

A fast, vigorous tree needs little chemistry. Keep insecticidal soap or neem for aphids, ant baits or barriers to break the ant-aphid link, Bt or spinosad for budworm, webworm and caterpillars, protein-bait or pheromone traps plus pod bagging for fruit fly, and a copper or biological fungicide for damping-off and cankers. Clean pruning tools and good drainage are the main defenses.