How and Where to Plant Paulownia?
Recommendations for Starting Your Paulownia Cultivation
Planting Paulownia is a medium-term investment with high return potential, but success depends entirely on choosing the right location and preparing the area properly. Before planting Paulownia, it is essential to understand climate, soil, land preparation, irrigation, spacing and early management. This guide brings together the main technical recommendations so you can evaluate the potential of your property and plan a Paulownia plantation with confidence.
This content explains:
• where to plant
• how to prepare the soil
• how to choose the seedling
• spacing
• irrigation
• pruning
• threats
• practices that increase productivity
Where to Plant Paulownia
Choosing the right place:
1) Temperature
The Paulownia tree, or Japanese Kiri, is found in subtropical, tropical and temperate regions.
Paulownia can adapt to a wide range of temperatures, but for maximum growth it is recommended that it stays in the 24–33 ºC range.
Plantations are usually established in spring and autumn in order to avoid frosts that occur after the first shoots appear, which damage the cellular structure of the leaves. Young trees tend to be more sensitive to low temperatures during the first two years of cultivation.
2) Altitude
Paulownia species can grow in areas up to 2,000 meters in altitude, but their growth is more vigorous in areas between 700 and 800 meters.
3) Soil Characteristics
Paulownia is a highly adaptable species and grows well in many soil types. The most suitable and recommended are light, well‑drained, sandy soils.
Soils with more than 30% clay and porosity below 50% are not recommended for Paulownia. Very compact, heavy, rocky, clayey soils and areas subject to flooding will likely prevent good tree development.
Another important factor is salinity. Japanese Kiri does not tolerate salinity above 1%.
4) Soil Depth
Deep, well‑drained soils are recommended.
The soil layer should be at least 2 meters deep so the root system has enough space to develop.
5) Soil pH
Soils with pH from 5.0 to 8.0 are best for Paulownia development.
6) Topography
It is possible to grow Paulownia on steep slopes, but this will obviously increase operating costs (irrigation, maintenance and harvesting).
In addition, trunk form can be affected by uneven sunlight and strong winds, which may result in lower‑quality timber.
7) Rainfall
An annual rainfall of at least 800 mm is recommended for good growth of Japanese Kiri. Otherwise, the plantation must be equipped with an irrigation system.
8) Wind
Areas with winds above 45 km/h should be avoided for Paulownia plantations.
Winds up to 30 km/h are not ideal, but the situation can be mitigated by installing stabilizers during the first year of development, until a strong woody stem is formed.
9) Sunlight
Paulownia requires a lot of sun for ideal growth. Although it is a fast‑growing tree, it is very thermophilic and in its early stages does not tolerate competition for light.
For this reason, spacing of 4x4 m or 5x5 m is recommended.
10) Air Humidity
High humidity increases the risk of microbial pathogens (especially fungi). Paulownia should therefore ideally be planted in a sheltered area, with low wind speed and low risk of summer storms.
11) Easy Access
When choosing the site, access for tractors, trucks and agricultural machines must be considered. The harvested wood volume is significant – one hectare can represent up to eight truckloads.
12) Legal Status
The plantation site must not be located in any protected area (wildlife sanctuary, national park, natural forest, etc.). We recommend checking the legality of your project with the relevant authorities in your region.
How to Prepare the Land to Plant Paulownia
Now that you know where to plant Kiri Paulownia, let’s move on to land preparation.
13) Ploughing the soil
Before planting, it is recommended to plough the soil to at least 40–60 cm to increase oxygenation and remove roots of weeds and perennial shrubs. If the soil is heavy and clayey, trenches should be 70–80 cm deep.
If you are converting pasture areas to Paulownia, the land should be worked at least 4–5 weeks before planting.
The area must be cleared before planting, and any regrowth of weeds must be strictly controlled.
14) Land leveling
It is necessary to level the land once or twice. After that, the area is ready for furrowing, staking and, finally, planting.
15) Furrows
Furrows should be about 20 cm deep. It is advisable to mix manure into the soil inside the furrows where Paulownia seedlings will be planted.
The tree must be planted so that the stem is fully exposed, level with the soil. During winter, it is recommended to build a mound of manure so the soil level rises at the planting point. The mound should be 25–30 cm higher than the surrounding ground.
16) Fertilization
Fertilization should always be defined based on soil analysis, since each area has different levels of nutrients, organic matter, pH and water‑holding capacity. This assessment indicates exactly:
• which nutrients are lacking
• which are in excess
• which corrections are truly necessary
• the appropriate amount of organic matter
• which fertilizers should be used and in what proportions
When soil analysis has not yet been carried out, it is recommended to:
• use a well‑stabilized source of organic matter at planting
• apply base fertilizers suited to the area profile, under technical guidance
• avoid heavy fertilization without diagnosis, as it can harm Paulownia root development
After the plantation is established, it is important to reassess the soil periodically, especially after the first cut, to adjust nitrogen, phosphorus, potassium and other nutrients to the growth rate of the crop.
17) Irrigation
Irrigation is one of the most important factors to ensure good establishment and rapid growth of Paulownia in the first months after planting. Although the species tolerates short dry periods, its initial performance is much better when there is regular water availability.
• Irrigate whenever the soil shows low moisture in the surface and subsurface layers. The ideal is to keep the soil moist, but never waterlogged.
• During seedling establishment, irrigation should be more frequent, especially in regions with irregular rainfall or high evapotranspiration.
• After the initial period, irrigations can be spaced out, maintaining only minimum moisture levels that ensure continuous development.
• In prolonged droughts, supplemental irrigation is essential, since water shortage significantly reduces the growth rate, even if it does not kill the plant.
• In more technical systems, soil moisture should be monitored using tensiometers, sensors or direct observation, to adjust frequency and volume according to weather conditions.
• Water with high salinity should be avoided, as it compromises nutrient uptake and growth.
• In regions with low annual rainfall, the project must be planned from the outset with an irrigation system (drip, micro‑sprinkler or hybrid).
Planting Kiri Paulownia Seedlings
Land prepared! Now let’s move on to how to plant Paulownia.
18) Choosing the seedling
If the goal is to produce Paulownia wood with good mechanical properties and appearance, then we need long, straight, knot‑free trunks. Each variety has a well‑defined morphology. Paulownia is often classified by crown shape: dense and wide (Paulownia tomentosa), semi‑wide (Paulownia elongata), narrow (Paulownia fortunei) and some of their hybrids.
At Paulownia Brasil, we work with four hybrids that have adapted very well to different regions of Brazil and produce high‑quality wood when properly managed. To buy Paulownia seedlings, click here.
19) Spacing between Paulownias
A 4 x 4 meter spacing (625 trees per hectare) has been the most common arrangement in plantations.
20) Intercropping Kiri with other crops
Annual vegetables, such as peas and beans, can be grown between Kiri rows with little impact on the trees in terms of water and nutrient loss. Even when they decompose at the end of the season, they enrich the soil with nitrogen.
Initial Management and Care
21) Threats to Paulownia cultivation
Like other species, Paulownia seedlings must be well protected from herbivorous animals.
As mentioned earlier, Paulownia should not be planted in areas prone to flooding, strong winds and low sunlight incidence.
22) Pruning
Any shoot emerging from the trunk just above the large leaves should be cut, taking great care not to remove the large leaves directly attached to the trunk.
Paulownia leaves are the tree’s solar panels – they capture sunlight and, together with water and nutrients, convert it into growth.
Removing these leaves slows Paulownia growth.
Branches not removed during the first year may result in loss of height growth potential, but they can be removed later without significant long‑term damage.
For a clean trunk up to five or six meters, pruning is recommended during the first three to four years.
Severe pruning can inhibit normal crown formation and even prevent natural tree development, resulting in slower diameter growth of the Paulownia trunk.
23) Weed control
Weed control promotes plant growth and vigor. A circle with a 1.5 m diameter around each tree should be kept free of weeds for at least the first 2 years. If young shoots (suckers) appear around the tree, they should be removed manually and not with herbicides.
Even with all these general recommendations, each area is unique in climate, soil, topography and land‑use history.
For projects from 3 hectares upward, we strongly recommend a complete technical assessment, including soil analysis, microclimate study, spacing definition and management planning.
If you have an area and want to understand whether it is suitable for Paulownia, we can help from diagnosis through to timber sale.