Maintenance

Watering

In Guatemala the need for watering depends on where the farm is located and how marked the rainy season is. In areas with a well-defined rainy season, the rain is usually enough to keep the tree hydrated all year, provided the trees are planted at the start of the rainy season. Paulownia is a deciduous species, meaning it loses all its leaves in the dry season (in areas where the two seasons are clearly marked); this adaptation lets it get through the dry season without any trouble. In other areas where it rains all year round, the trees lose their leaves only partially, so there is no need for watering.

If the farm is in the dry zone of the country and has an irrigation system, it does no harm to irrigate the trees during critical periods of drought.

We recommend applying water retainers BEFORE planting; there are several brands, and prices vary by area. Ask our technical advisor which product is available in your region and what the ideal dose is for your site. This reduces the risk if there is a dry spell between rains: the weather is very changeable and we cannot know whether a weather event will affect us at or after planting.

In case of drought after planting

Water every other day, or 2 days a week, so the trees establish well if the soil is dry or there has been little rain (about 5 gallons per tree per week). Your young trees will benefit from less water more often, as this trains the roots to grow deep into the soil. You will need to keep watch all summer to make sure the soil does not dry out. It is much easier to under-water than to over-water.

Do's and don'ts

DO WATER with a deep, slow soak of about 1 to 2 gallons every 2 days. The minimum amount of water is 5 gallons per plant per week. This lets the main roots grow deep into the soil.
DO NOT spray water on the leaves in hot weather.
DO NOT keep the soil around the roots constantly wet; let the surface soil around the tree dry before watering again.
DO NOT panic if the leaves droop during the heat of the day. If the roots are healthy, the leaves will perk up in the morning.

Fig. 2. Watering zone: the area under the canopy, bounded by the drip line.

Weed control

Weed control is essential during the first growing season. The aim is to make sure weeds do not overtake the young trees. Keep an area of 1.5 m or more around the tree free of weeds. It is important to balance controlling competition with keeping the ground covered: we have found that farms with enough ground cover have had better survival and early growth. There are many ways to control weeds, including manual and/or mechanical removal and herbicides. Consult a World Tree representative before using any herbicide not listed below.

Manual and mechanical removal

Clearing weeds and taller green grasses near the tree's stem is best done by hand or mechanically (that is, pulling, cutting, crimping or beating down the weeds) to avoid the risk of herbicide touching the tree.

Non-systemic herbicides

This herbicide is useful for controlling broadleaf weeds and grasses in the tree circle. Always take all the required precautions and, as far as possible, use clean water. Recommended rate: 6 ounces per backpack sprayer. Use on weeds that are free of standing water or excessive moisture. Never apply to Paulownia trees.

Acetochlor

This herbicide is useful for controlling broadleaf weeds and grasses in the tree circle. Use it on trees at least 6 months old, and only where the tree circles have been very well maintained; the tree circle needs to be bare, moist soil. The rate is 6 ounces per 20-liter sprayer.

Fluazifop-p-butyl

This herbicide is useful for controlling grasses, especially when they are no taller than 20 cm. If the grasses are taller, we recommend cutting them, waiting at least a week for them to resprout well, and then applying the product. Recommended rate: 6 ounces per 20-liter sprayer.

Avoid glyphosate

Use products that do not contain glyphosate. Even if the tree is still dormant, glyphosate can be absorbed through the bark of its young stems. Contact with small amounts of glyphosate will kill a Paulownia tree.

When considering any other herbicide, read the labels carefully and consult your World Tree representative before buying or applying it. Once again, take great care when applying herbicides to avoid any contact with the Paulownia trees.

Soil amendments

Soil amendment and fertilizer in the first year

Fertilizing in the first year of growth, like water, is a deciding factor for growth. Your soil analyses are essential for determining what type of fertilizer to use and how much to apply. You should fertilize at least twice a year.

As soon as planting is finished we go straight on to liming, adding soil amendment at the recommended rate (on average 500 grams per tree), evenly over the whole tree circle and trying not to let any product fall on the tree.
From 3 to 7 days after planting, provided there is moisture, we recommend fertilizing with a complete chemical fertilizer. The amount will be given by the World Tree advisor, depending on your soil analyses.
From 14 to 16 weeks after the first application, we recommend a second application with a chemical fertilizer. This second application could be split in two so the tree can take up nutrients more often. The amount of fertilizer and the number of applications will be given by the World Tree advisor, depending on your soil analyses and on climate and site conditions.
If the leaves are dark green, the trees are getting enough fertilizer. Pale green leaves mean they are not getting enough nutrition. Yellowing of the older leaves toward the bottom of the stem is normal.
During the growth phase other products will also be applied for the healthy development of the trees, to prevent and reduce the incidence of pests and diseases.

Nitrogen

Stimulates leaf growth and a rich, deep green color.

Phosphorus

Helps stimulate root growth and flowering.

Potassium

Used by plants to regulate water use and withstand various stresses.

Soil amendments and fertilizers in the following years

We recommend having soil tests processed at your local extension office for at least the first few years, at the start of the dormant season. This will help you plan your soil amendment and fertilizer needs for the coming year.
Soil amendment should be added to the soil at the start of the rainy season and before applying fertilizer, or else at the end of the rainy season, so it has a few months to work into the soil and neutralize acidity. It should be applied before rain, so that it dissolves into the soil; soil amendment can be blown away by the wind if the timing is wrong. Spread the amendment widely over the tree circle at the rates recommended for your soil type.
The start of the rainy season is the right time to fertilize; we recommend a complete chemical fertilizer scattered over the tree circle, without touching the trunk of the tree.
Fertilizer must be applied BEFORE coppicing, if coppicing is needed.
To grow well the tree needs timely supplies of nutrients. We recommend chemical fertilizing two to three more times after the application made at the start of the rains.
Work out the amount to apply from your soil analysis. Spread the fertilizer evenly on the soil surface, in a circle with a radius of about one third of the tree's height (a radius of 50 cm around the trunk for a tree of 1.50 m to 2 m; for a tree 5 m tall, a radius of 1.5 m). Do not apply any fertilizer within 30 cm of the trunk; there are few feeder roots there.